only build on master push

.github/workflows/build.yml

@@ -1,20 +1,14 @@
 name: Build-CI
 
-on: [pull_request_target, push]
+on:
+    push:
+      branches:
+        - master
 
 jobs:
 
-  approve: # First step
-    runs-on: ubuntu-latest
-
-    steps:
-    - name: Approve
-      run: echo For security reasons, all pull requests to this repository need to be approved first before running any automated CI.
-
   build:
     runs-on: ubuntu-latest
-
-    needs: [approve] # Require the first step to finish
     environment:
       name: IO
     steps: