Update dependabot.yml

Author: quittle

.github/workflows/dependabot.yml

@@ -10,4 +10,4 @@ jobs:
             - uses: actions/checkout@v2
             - uses: ahmadnassri/action-dependabot-auto-merge@v2
               with:
-                  github-token: ${{ secrets.mytoken }}
+                  github-token: ${{ secrets.GITHUB_TOKEN }}