Hardening the CI in relation to PRs

Author: SailReal

.github/workflows/build.yml

@@ -1,6 +1,8 @@
 name: Build
 on:
-  [push]
+  push:
+  pull_request_target:
+    types: [labeled]
 jobs:
   build:
     name: Build and Test
@@ -46,4 +48,4 @@ jobs:
         with:
           token: ${{ secrets.CRYPTOBOT_RELEASE_TOKEN }}
           generate_release_notes: true
-          prerelease: true
+          prerelease: true