Uses GITHUB_TOKEN in scala-steward

Note that this has some implications specified in here: https://github.com/marketplace/actions/scala-steward-github-action#using-the-default-github-action-token

Author: albertpastrana

.github/workflows/scala-steward.yml

@@ -13,4 +13,4 @@ jobs:
       - name: Launch Scala Steward
         uses: scala-steward-org/scala-steward-action@v2
         with:
-          github-token: ${{ secrets.ADMIN_GITHUB_TOKEN }}
+          github-token: ${{ secrets.GITHUB_TOKEN }}