This pull request adds a license, such as `MIT` or `Commercial`, to
generated `Pods-{Project}-acknowledgements.plist`. I send this PR
because I want to filter some licenses by their types. It is useful to
show licenses only for open libraries, not private libraries.

Use gh-issues-inspector to improve error reporting 

Avoid use of `activesupport` version 5

Version 5 of `activesupport` requires Ruby version >= 2.2.2 which breaks
fresh installations using system Ruby, which is still 2.0, even on macOS
10.12.

Update to use the latest GHInspector

Fix the API urls for the gh-inspector

Removed extra bug fixes section in CHANGELOG.md

Also put "Improve handling of app extensions…" back into enhancements, where I moved it during the PR

[Installer] Print message when skipping user project integration

Fix shellscript in '📦 Check Pods Manifest.lock'

Require active_support in xcconfig_helper

This ensures that scripts like xcpretty can differentiate default output
and error output.

The script is integrated using /bin/sh but [[ is not defined in generic
POSIX shell. Confirm shellcheck error:

if [[ $? != 0 ]] ; then
   ^-- SC2039: In POSIX sh, [[ ]] is undefined.

This works right now, because on common OS X systems, /bin/sh is Bash.
But this might change in the future.

[Installer] Use user defined swift version

Improve handling of app and watch os 1 extensions

[Installer] Verify no duplicate static libs

Fix code signing in Xcode 8

This sets `CODE_SIGN_IDENTITY` to empty for all generated aggregate and
Pod targets.

[repo/push] allow URLs for pushing to private repos