GH Actions improvements

Allow manual workflow runs and update the checkout action version

.github/workflows/main.yml

@@ -9,6 +9,7 @@ on:
     branches: [ main ]
   pull_request:
     branches: [ main ]
+  workflow_dispatch:
 
 # A workflow run is made up of one or more jobs that can run sequentially or in parallel
 jobs:
@@ -20,7 +21,7 @@ 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
 
     - name: Install build dependencies via homebrew
       run: |