Open a PR to all model deployment repositories upon creation of new vX branch

[CodeGat]

Currently, we have to create PRs manually for all model deployment repositories that we support. We use branch references for the most part, but allow tag references for the reusable workflows within this repository.

Upon creation of a new major version of the infrastructure, open PRs to all supported model deployment repositories.

[CodeGat]

To get all deployment repositories:

gh search repos --owner access-nri --json name --jq '[.[].name] | @sh' -- topic:deployment -topic:template