CI: Set deploy workflow concurrency

.github/workflows/main_deploy.yaml

@@ -5,6 +5,10 @@ on:
     branches:
       - main
 
+concurrency:
+  group: main_deploy
+  cancel-in-progress: true
+
 env:
   FLUTTER_VERSION: ${{ secrets.FLUTTER_VERSION }}
   JAVA_VERSION: ${{ secrets.JAVA_VERSION }}

.github/workflows/pull_request.yaml

@@ -1,6 +1,6 @@
 name: Pull Request Workflow
 
-on: [push, pull_request]
+on: [pull_request]
 
 env:
   FLUTTER_VERSION: ${{ secrets.FLUTTER_VERSION }}