[deb] Include an InRelease file in the apt.vector.dev repository

[wraithm]

An InRelease file is just a Release file that's signed inline. If a repo has a Release and Release.gpg file, you can just ignore the InRelease file.

I've found that apt-s3 fails when the InRelease file is missing: zendesk/apt-s3#17

I could imagine that other apt related tools fail without the InRelease file... The old repositories.timber.io repo included this InRelease file.

In the meantime, I'm going to try to fix apt-s3 to not fail when the InRelease file is missing.