Add GitHub option back to start page in VS2017

[meaghanlewis]

Tested on:
Visual Studio version: VS2017, 15.4.3

This option was apparent in the last GHfVS release v2.3.4.54 but stopped working after that.
I notice the icon disappear after #1282 was merged to master, but am not sure about the exact commit

What happened
Open VS2017 with the latest dev build on master and look on the start page.

Expected: GitHub option is present

Actual: GitHub option is not present

[grokys]

Ok, strange - just tried this on master in the experimental instance and it's working, but can confirm it's not working with the package from CI.

[grokys]

One thing I notice is that in the experimental instance the Start Page package is listed under Extensions and Updates:

However in the main instance it isn't:

My guess is that something in #1282 broke installing the secondary package.

[shana]

Likely this was broken by the fact that the GitHub.StartPage.pkdgef file was no longer included in the vsix. @meaghanlewis Could you test https://ci.appveyor.com/project/github-windows/visualstudio/build/2.3.5.307 and see whether this guess is correct and the start page is indeed fixed?

[meaghanlewis]

Yes, this issue is indeed fixed in build 2.3.5.307. Thanks @shana 🎉