Use spaces for yaml actions

Author: ooade

.github/workflows/build-test-code.yml

@@ -1,17 +1,17 @@
 name: Test code on pull request
 
 on:
-	pull_request:
-		branches: [main]
+  pull_request:
+    branches: [main]
 
 jobs:
-	test_pull_request:
-		runs-on: ubuntu-latest
-		steps:
-			- uses: actions/checkout@v2
-			- uses: actions/setup-node@v1
-				with:
-					node-version: 12
+  test_pull_request:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v1
+        with:
+          node-version: 12
       - run: npm ci
       - run: npm test
       - run: npm run build