Add git action for flags (#1005)

.github/workflows/flags.yml

@@ -0,0 +1,16 @@
+name: Test Flags
+
+on: pull_request
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Setup Python
+        uses: actions/setup-python@v4.0.0
+        with:
+          python-version: '3.x'
+          architecture: 'x64'
+      - name: Test flags
+        run: python flags.py

flags.py

@@ -35,3 +35,5 @@ for code in country_codes:
 
 if all_good:
     print("All flag icons and country.json are in sync.")
+    exit(0)
+exit(1)