Add a git tag for MELPA Stable

[juanfra684]

The project doesn't have any git tag, so MELPA will never publish the mode in MELPA stable. Could you add a git tag to the repo?.

[tmtvl]

.oO(If we are going to start tagging releases for MELPA stable it may also be prudent to switch over to a more git-flow-esque style of managing the repo.)

[matiaslina]

I think we can tag it as version 0.1.0 now or after #35 is merged.

After that we should keep the changes/PR on a devel branch. That's what you mean with a more git-flow-esque style @tmtvl ?

[tmtvl]

I've created the 0.1.0 tag here: https://github.com/Raku/raku-mode/releases/tag/0.1.0