docs: run only on new tag note on github actions (#1306)

* docs: run only on new tag note on github actions

* Complete example

www/content/actions.md

@@ -46,6 +46,30 @@ jobs:
 > **IMPORTANT**: note the `Unshallow` workflow step. It is required for the
 > changelog to work correctly.
 
+If you want to run GoReleaser only on new tag, you can use this event:
+
+```yaml
+on:
+  push:
+    tags:
+      - '*'
+```
+
+Or with a condition on GoReleaser step:
+
+```yaml
+      -
+        name: Run GoReleaser
+        uses: goreleaser/goreleaser-action@v1
+        if: startsWith(github.ref, 'refs/tags/')
+        with:
+          version: latest
+          args: release --rm-dist
+          key: ${{ secrets.YOUR_PRIVATE_KEY }}
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+```
+
 > For detailed instructions please follow GitHub Actions [workflow syntax][syntax].
 
 ## Customizing