Cleanup and improve robustness of Github actions.

.github/workflows/sonarqube-scan.yml

@@ -1,36 +1,34 @@
+# This workflow requires the following configuration in Github
+#
+# Variables:
+#   SONARQUBE_PROJECT_KEY - The project key in SonarQube
+#
+# Secrets:
+#   SONARQUBE_TOKEN - SonarQube API token
+#   SONARQUBE_HOST - The URL of the SonarQube host
+
 name: SonarQube scan
 
 on:
-  # Triggers the workflow on push events but only for the "master" branch
   push:
     branches: [ "master" ]
 
-  # Allows you to run this workflow manually from the Actions tab
-  workflow_dispatch:
-
-# Concurrent SonarQube runs can cause problems if they report times out of order
 concurrency:
   group: sonarqube
   cancel-in-progress: false
 
-# A workflow run is made up of one or more jobs that can run sequentially or in parallel
 jobs:
-
-  # This workflow contains a single job called "build"
   build:
+    # Only run if the project key is set
     if: vars.SONARQUBE_PROJECT_KEY != null
 
-    # The type of runner that the job will run on
     runs-on: ubuntu-latest
 
-    # 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@v3
         with:
           fetch-depth: 0
 
-      # Run the scan
       - name: Create the scan properties file
         run: |
           cat <<EOF > sonar-project.properties