Add auto update check for templates and trigger workflow from package…

[dennismeister93]

This PR adds a workflow to be synced into our templates/sdk repos.

It enables:

1. a scheduled check every day for possible updates and PR creation
2. an automatic trigger for a devenv-* package when a release is created

[erikbosch]

I think this one is good enough to merge, we will anyway not detect potential corner cases until we have merged it.

[MP91]

lets try it, since it is just creating PRs it shouldn't be a big issue