feat(ci): use separate github app for lgtm workflow. (#5365)

Signed-off-by: Erik Westra <e.s.westra.95@gmail.com>

.github/workflows/lgtm.yml

@@ -29,8 +29,8 @@ jobs:
       id: generate_token
       uses: actions/create-github-app-token@67018539274d69449ef7c02e8e71183d1719ab42 # v2.1.4
       with:
-        app-id: ${{ secrets.APP_ID }}
-        private-key: ${{ secrets.PRIVATE_KEY }}
+        app-id: ${{ secrets.LGTM_APP_ID }}
+        private-key: ${{ secrets.LGTM_PRIVATE_KEY }}
         owner: ${{ github.repository_owner }}
 
     - name: Slash Command Dispatch