go-cache-plugin is a GOCACHEPROG implementation that backs the Go build cache with S3, wanted via dnf on workstations and estate hosts. Upstream publishes no tags or releases, so the build pins a commit and the version is that commit's date.
- Add `rpms/go-cache-plugin` metadata, build.sh and nfpm.yaml
- Compile `cmd/go-cache-plugin` at commit 3031b5d with `GOTOOLCHAIN=go1.26.1`
- Ship the single binary at `/usr/bin/go-cache-plugin`
- Build for almalinux/el9 and fedora 42/43/44
Reviewed-on: #174
Co-authored-by: unkin-agent <unkin-agent@unkin.net>
Co-committed-by: unkin-agent <unkin-agent@unkin.net>
