Added github action to convert to Deno

[oscarotero]

This PR adds a github action that is runned after creating new tags, so it will update automatically the code in the https://github.com/postcss/postcss-deno-import repository (the Deno version of the plugin) and create the same tag there.

The only requirement is a secret variable with a PAT that have writting access to postcss-deno-import repository in order to commit the changes and create the new tag. So, after merging this PR, you have to:

• Go to Settings > Secrets of this repository
• Click in "New Secret"
• The secret name is PAT, and the value the access token

That's all.

[RyanZim]

In regards to the personal access token stuff, I'm not comfortable putting a PAT for my account into the secrets here, especially when I haven't fully vetted the toolchain used in the action. @ai how does postcss repo do this? Should we have a bot GH account for this?

[romainmenke]

Is this still needed?

https://deno.land/[email protected]/node

Deno now has improved support for npm packages.

[oscarotero]

It's not needed. I'm using the npm version on Deno without problems (https://github.com/lumeland/lume/blob/master/deps/postcss.ts)

I'm closing this.

[romainmenke]

Thank you for the fast response 🙇