Create GitHub workflow for refreshing individual files

[mgeisler]

It should be possible to create a GitHub workflow which runs

MDBOOK_OUTPUT='{"xgettext": {"pot-file": "messages.pot"}}' mdbook build -d po
msgmerge --update po/XX.po po/messages.pot

for a language. I believe it's also possible to trigger workflows directly in the Actions tab. The workflow could then do the msgmerge, open a PR and perhaps even close the PR automatically.

[dtee1]

Could this be assigned to me?

[mgeisler]

Hi @dtee1, sure! Please let us know if you run into any problems with this!

[mgeisler]

I don't think this is super important, and with the idea of using a translation platform (#1305), we won't need this going forward.