GitHub Apps: Replace grafanabot token with grafana-delivery-bot GitHub App (#70242)

* Update bump-version.yml

* Fix secret

* [REVERTME] Remove check

* Test without grafana-delivery-bot prefix

* Check if token exists

* Cleanup bump-version

* Update gh actions to use app key

.github/workflows/milestone.yml

@@ -7,15 +7,27 @@ on:
         required: true
 jobs:
   call-remove-milestone:
-    uses: grafana/grafana/.github/workflows/remove-milestone.yml@main
-    with:
-      version_call: ${{ github.event.inputs.version_input }}
-    secrets:
-      token: ${{ secrets.GH_BOT_ACCESS_TOKEN }}
+    - name: "Generate token"
+        id: generate_token
+        uses: tibdex/github-app-token@b62528385c34dbc9f38e5f4225ac829252d1ea92
+        with:
+          app_id: ${{ secrets.GRAFANA_DELIVERY_BOT_APP_ID }}
+          private_key: ${{ secrets.GRAFANA_DELIVERY_BOT_APP_PEM }}
+    - uses: grafana/grafana/.github/workflows/remove-milestone.yml@main
+      with:
+        version_call: ${{ github.event.inputs.version_input }}
+      secrets:
+        token: ${{ steps.generate_token.outputs.token }}
   call-close-milestone:
-    uses: grafana/grafana/.github/workflows/close-milestone.yml@main
-    with:
-      version_call: ${{ github.event.inputs.version_input }}
-    secrets:
-      token: ${{ secrets.GH_BOT_ACCESS_TOKEN }}
-    needs: call-remove-milestone
+    - name: "Generate token"
+        id: generate_token
+        uses: tibdex/github-app-token@b62528385c34dbc9f38e5f4225ac829252d1ea92
+        with:
+          app_id: ${{ secrets.GRAFANA_DELIVERY_BOT_APP_ID }}
+          private_key: ${{ secrets.GRAFANA_DELIVERY_BOT_APP_PEM }}
+    - uses: grafana/grafana/.github/workflows/close-milestone.yml@main
+      with:
+        version_call: ${{ github.event.inputs.version_input }}
+      secrets:
+        token: ${{ steps.generate_token.outputs.token }}
+      needs: call-remove-milestone