we can use setup-go's cache again, since it does not correctly handle
concurrent workflows that may produce a cache. Previously all jobs
that called setup-go would get an empty cache, and would have to
download the all of the modules every time.
the unit-tests (bats tests) will be run as part of a release
Merge test and build workflows
Some benefits of this change:
See https://github.com/hashicorp/vault-secrets-operator/actions/caches?query=sort%3Asize-asc for list of incomplete caches. They have size in the range of 4KB-5KB
Proper cache example: https://github.com/hashicorp/vault-secrets-operator/actions/runs/9370160932/job/25797062513?pr=795#step:3:28