This my be completely silly - I am reporting it nevertheless for the case it is not 
Few minutes ago while using the editor, a new tab was auto-created and contained instructions on how to run an update:
Paying attention not to include the leading two spaces of the supplied script, I ran it in the ST console and got the following
[quote]DPI scale: 1
startup, version: 3065 windows x64 channel: stable
executable: /C/Program Files/Sublime Text 3/sublime_text.exe
working dir: /C/work/Learning/ResponsiveWebDesign/marcotte/rwd-samplefiles
packages path: /C/Users/Nikolaj/AppData/Roaming/Sublime Text 3/Packages
state path: /C/Users/Nikolaj/AppData/Roaming/Sublime Text 3/Local
hardware concurrency: 4
zip path: /C/Program Files/Sublime Text 3/Packages
zip path: /C/Users/Nikolaj/AppData/Roaming/Sublime Text 3/Installed Packages
found 6 files for base name Default.sublime-keymap
found 2 files for base name Default.sublime-mousemap
found 5 files for base name Main.sublime-menu
loading bindings
loading pointer bindings
found 1 files for base name Default.sublime-theme
theme loaded
app ready
wrote startup cache, added files: 1 orphaned files: 0 total files: 190 cache hits: 189
pre session restore time: 0.077405
startup time: 0.100405
first paint time: 0.101405
launching: /C/Program Files/Sublime Text 3/plugin_host.exe
reloading plugin Default.block
reloading plugin Default.comment
reloading plugin Default.copy_path
reloading plugin Default.delete_word
reloading plugin Default.detect_indentation
reloading plugin Default.duplicate_line
reloading plugin Default.echo
reloading plugin Default.exec
reloading plugin Default.fold
reloading plugin Default.font
reloading plugin Default.goto_line
reloading plugin Default.history_list
reloading plugin Default.indentation
reloading plugin Default.kill_ring
reloading plugin Default.mark
reloading plugin Default.new_templates
reloading plugin Default.open_file_settings
reloading plugin Default.open_in_browser
reloading plugin Default.pane
reloading plugin Default.paragraph
reloading plugin Default.paste_from_history
reloading plugin Default.save_on_focus_lost
reloading plugin Default.scroll
reloading plugin Default.set_unsaved_view_name
reloading plugin Default.side_bar
reloading plugin Default.sort
reloading plugin Default.swap_line
reloading plugin Default.switch_file
reloading plugin Default.symbol
reloading plugin Default.transform
reloading plugin Default.transpose
reloading plugin Default.trim_trailing_white_space
reloading plugin CSS.css_completions
reloading plugin Diff.diff
reloading plugin HTML.encode_html_entities
reloading plugin HTML.html_completions
reloading plugin AngularJS.AngularJS-sublime-package
reloading plugin AngularJS.jscompletions
reloading plugin AngularJS.message
reloading plugin AngularJS.sublime_commands
reloading plugin AngularJS.viewlocation
reloading plugin Emmet.emmet-plugin
reloading plugin Nettuts+ Fetch.Fetch
reloading plugin Package Control.Package Control
loaded 1014 snippets
reloading plugin SnippetMaker.snippet_maker
reloading plugin SublimeCodeIntel.SublimeCodeIntel
plugins loaded
Emmet: No need to update PyV8
Package Control: Installing 1 upgrades
reloading Packages/User/Preferences.sublime-settings
found 1 files for base name Default.sublime-theme
theme loaded
Could not import subprocess32 module, falling back to subprocess module
Exception in thread Thread-5:
Traceback (most recent call last):
File ā./threading.pyā, line 901, in _bootstrap_inner
File ā./threading.pyā, line 858, in run
File āpackage_control.automatic_upgrader in C:\Users\Nikolaj\AppData\Roaming\Sublime Text 3\Installed Packages\Package Control.sublime-packageā, line 198, in do_upgrades
File āpackage_control.package_manager in C:\Users\Nikolaj\AppData\Roaming\Sublime Text 3\Installed Packages\Package Control.sublime-packageā, line 749, in install_package
PermissionError: [WinError 32] The process cannot access the file because it is being used by another process: āC:\Users\Nikolaj\AppData\Roaming\Sublime Text 3\Installed Packages\Package Control.sublime-packageā
reloading Packages/User/Package Control.sublime-settings
reloading Packages/User/Fetch.sublime-settings
import urllib.request,os; pr=āPreferences.sublime-settingsā; ip=āignored_packagesā; n=āPackage Controlā; s=sublime.load_settings(pr); ig=s.get(ip); ig.append(n); s.set(ip,ig); sublime.save_settings(āPreferences.sublime-settingsā); pf=n+ā.sublime-packageā; urllib.request.install_opener(urllib.request.build_opener(urllib.request.ProxyHandler())); by=urllib.request.urlopen(āhttps://packagecontrol.io/ā+pf.replace(ā ā,ā%20ā)).read(); open(os.path.join(sublime.installed_packages_path(),pf),āwbā).write(by); ig.remove(n); s.set(ip,ig); sublime.save_settings(pr); print(āPackage Control: 3.0.0 upgrade successful!ā)
ignored packages updated to: [Vintage, Emmet Css Snippets, View In Browser, SideBarEnhancements, Package Control]
unloading plugin Package Control.Package Control
reloading Packages/Package Control/Package Control.sublime-settings
found 4 files for base name Main.sublime-menu
found 1 files for base name Default.sublime-theme
170998
ignored packages updated to: [Vintage, Emmet Css Snippets, View In Browser, SideBarEnhancements]
found 1 files for base name Default.sublime-theme
Package Control: 3.0.0 upgrade successful!
reloading plugin Package Control.bootstrap
reloading plugin Package Control.Package Control
reloading Packages/Package Control/Package Control.sublime-settings
found 5 files for base name Main.sublime-menu
reloading Packages/User/Preferences.sublime-settings
theme loaded
theme loaded
found 1 files for base name Default.sublime-theme
theme loaded
reloading Packages/User/Package Control.sublime-settings
reloading plugin 0_package_control_loader.00-package_control
Package Control: Channel packagecontrol.io/channel_v3.json does not appear to be a valid channel file because the āschema_versionā is not a valid number.
Package Control: Channel packagecontrol.io/channel_v3.json does not appear to be a valid channel file because the āschema_versionā is not a valid number.
Package Control: No updated packages
[/quote]