In the new build promotion workflow, MONGO_VERSION will be sourced from a file checked into the server repo. In 8.0+, this file will be https://github.com/10gen/mongo/blob/master/.bazelrc.target_mongo_version. For 7.0 we should expect the file to be named differently and with different contents because we use scons there still instead of Bazel. We want to automate PRs that bump this version string (including the merge) on tag. We should skip over any alpha/rc/non-GA tags. When we tag a GA, we should increment the patch version counter by one. We can ignore the major.minor versions for now and make manual PRs for those on branch cut (perhaps automatable later on?).

There is a GitHub Action that Zack checked in with most of this sketched out, but we should test it out and ensure it works for all of the cases mentioned above.