Go upgrade:
- Go 1.23 is current => use that for release builds
- Go 1.22 is less than one year old, it's desirable to support it.
- The [`Go Toolchains`](https://go.dev/doc/toolchain) stuff is available
in both of these (would also be in Go 1.21). That is quite nice stuff,
but required some changes to how we versions we use in CircleCI and
the `release-docker` Makefile target.
Protobuf upgrade:
- Go to protobuf GH release website
- Download latest locally
- run `sha256sum`
- replace existing pinned hashes
- `make generate`
Deps upgrade:
- `go get -t -u all`
- repository moves aren't handled well automatically, fix manually
- repeat until no changes
