Error with the usage instructions

[lchannings-cais]

Hey,

The usage directs us to use zrosenbauer/slacktion@v1 for the latest v1 release, but the project does not have a v1 git ref.

GitHub Actions shows the error:

Error: Unable to resolve action `zrosenbauer/slacktion@v1`, unable to find version `v1`

Can you maintain a tag reference that points v1 at the latest 1.0 release? Or maybe update the docs to use @main instead?