feat: Include commit and date in version

[nitrocode]

what

• Include commit and date in version
• Allow forward slash make targets in make help

why

• When new versions are built, we will be able to see the exact commit hash on the pod/ec2 where atlantis is deployed as well as its user interface
• This will help a lot if people use the dev image tag which currently does not show its short git sha in the tag itself (except in the image labels)

tests

• I have tested my changes by running atlantis version locally

✗ go build -v -o atlantis .
✗ ./atlantis version
atlantis dev (commit: none) (build date: unknown)

With appropriate inputs that will come from goreleaser and in the Dockerfile

✗ go build -trimpath -ldflags "-s -w -X 'main.version=v0.99.0' -X 'main.commit=db70ffe' -X 'main.date=2022-02-24'" -v -o atlantis
✗ ./atlantis version
atlantis v0.99.0 (commit: db70ffe) (build date: 2022-02-24)

references

• Previous PR fix(docker): Set version based on release tag, revert gorelease signing #3051