add README checklist entry for adapting the workflow

Author: SillyFreak

README.md

@@ -13,6 +13,14 @@ A short description about the project and/or client.
   - See also the [typst/packages README](https://github.com/typst/packages/?tab=readme-ov-file#package-format)
 - [ ] Adapt Repository URLs in `CHANGELOG.md`
   - Consider only committing that file with your first release, or removing the "Initial Release" part in the beginning
+- [ ] Adapt or deactivate the release workflow in `.github/workflows/release.yml`
+  - to deactivate it, delete that file or remove/comment out lines 2-4 (`on:` and following)
+  - to use the workflow
+    - [ ] check the values under `env:`, particularly `REGISTRY_REPO`
+    - [ ] if you don't have one, [create a fine-grained personal access token](https://github.com/settings/tokens?type=beta) with [only Contents permission](https://stackoverflow.com/a/75116350/371191) for the `REGISTRY_REPO`
+    - [ ] on this repo, create a secret `REGISTRY_TOKEN` (at `https://github.com/[user]/[repo]/settings/secrets/actions`) that contains the so created token
+
+    if configured correctly, whenever you create a tag `v...`, your package will be pushed onto a branch on the `REGISTRY_REPO`, from which you can then create a pull request against [typst/packages](https://github.com/typst/packages/)
 - [ ] remove/replace the example test case
 - [ ] (add your actual code, docs and tests)
 - [ ] remove this section from the README