Add a new `github create backport` sub-command that can create a
backport of a given pull request. The command has been designed around a
Github Actions workflow where it is triggered on a closed pull request
event with a guard that checks for merges:
```yaml
pull_request_target:
types: closed
jobs:
backport:
if: github.even.pull_request.merged
runs-on: "..."
```
Eventually this sub-command (or another similar one) can be used to
implemente backporting a CE pull request to the corresponding ce/*
branch in vault-enterprise. This functionality will be implemented in
VAULT-34827.
This backport runner has several new behaviors not present in the
existing backport assistant:
- If the source PR was made against an enterprise branch we'll assume
that we want create a CE backport.
- Enterprise only files will be automatically _removed_ from the CE
backport for you. This will not guarantee a working CE pull request
but does quite a bit of the heavy lifting for you.
- If the change only contains enterprise files we'll skip creating a
CE backport.
- If the corresponding CE branch is inactive (as defined in
.release/versions.hcl) then we will skip creating a backport in most
cases. The exceptions are changes that include docs, README, or
pipeline changes as we assume that even active branches will want
those changes.
- Backport labels still work but _only_ to enterprise PR's. It is
assumed that when the subsequent PRs are merged that their
corresponding CE backports will be created.
- Backport labels no longer include editions. They will now use the
same schema as active versions defined .release/verions.hcl. E.g.
`backport/1.19.x`. `main` is always assumed to be active.
- The runner will always try and update the source PR with a Github
comment regarding the status of each individual backport. Even if
one attempt at backporting fails we'll continue until we've
attempted all backports.
Signed-off-by: Ryan Cragun <me@ryan.ec>