ci: Fix immutable releases

Github supports immutable releases. They can't be changed once
published. This is great, but the release action was broken and created
an immutable release, published it, and then tried to upload the dist
artifacts.

Upgrade to the latest version and explicitly create an immutable
release. In this version, the release action creates a draft release,
uploads the dist artifacts, and then publishes it.

Author: swick

.github/workflows/release.yml

@@ -69,9 +69,10 @@ jobs:
           echo $preRelease
 
       - name: Create release
-        uses: ncipollo/release-action@v1.15.0
+        uses: ncipollo/release-action@v1.20.0
         with:
           tag: ${{ env.releaseVersion }}
           body: ${{ env.releaseChangelog }}
           prerelease: ${{ env.preRelease }}
-          artifacts: _build/meson-dist/*
+          artifacts: _build/meson-dist/*
+          immutableCreate: true