[generate_manifest] use mcpm registry bot (#239)

Author: GabrielDrapor

.github/workflows/generate-manifest.yml

@@ -22,8 +22,8 @@ jobs:
         id: app-token
         uses: actions/create-github-app-token@v1
         with:
-          app-id: ${{ secrets.BOT_APP_ID }}
-          private-key: ${{ secrets.BOT_PRIVATE_KEY }}
+          app-id: ${{ secrets.MCPM_REGISTRY_BOT_APP_ID }}
+          private-key: ${{ secrets.MCPM_REGISTRY_BOT_PRIVATE_KEY }}
 
       - name: Checkout repository
         uses: actions/checkout@v4