Update existing blank.yml to support master and main branches

Co-authored-by: lippytm <65956507+lippytm@users.noreply.github.com>

Author: Copilot

.github/workflows/blank.yml

@@ -3,12 +3,12 @@
 name: CI
 
 # Controls when the action will run. Triggers the workflow on push or pull request
-# events but only for the master branch
+# events but only for the master or main branch
 on:
   push:
-    branches: [ master ]
+    branches: [ master, main ]
   pull_request:
-    branches: [ master ]
+    branches: [ master, main ]
 
 # A workflow run is made up of one or more jobs that can run sequentially or in parallel
 jobs:
@@ -20,7 +20,7 @@ jobs:
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps:
       # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
 
       # Runs a single command using the runners shell
       - name: Run a one-line script