Add pester to GitHub integration transport
Add pester to GitHub integration transport

We've seen production have issues POSTing to GitHub to refresh tokens
and it's happened more since the Analysis web page is being checked by
monitoring every few minutes from different locations.

I also see it running integration tests which causes the entire suite
to stop, so adding some retry logic appears to resolve the issue each
time.

bradleyfalzon/gopherci,bradleyfalzon/gopherci