[admin] Make opentelemetrybot push tags for us

[mx-psi]

To further reduce the manual work needed during releases, we want to explore automating pushing the tags from the release job.

@codeboten assigning this to you since you are already working on it IIUC.

Relates to #7576.

[Aneurysm9]

I don't believe we can use the bot for this as it is not supposed to have write permission to any repo.

Beyond any policy limitations with using the bot for this purpose, I have reservations around removing the requirement that the release manager sign the tags with a personal GPG key. I get that I'm probably in the minority in signing commits and tags with a key from an HSM, but I do find it valuable to know that a particular individual has reviewed and signed off on the release and worry about the potential for the automated creation of unauthorized releases that are indistinguishable from authorized releases.