CI: run on #verification #docs #sonar

.github/workflows/cetlvast.yml

@@ -1,8 +1,7 @@
 name: "CETLVaSt"
 
 on:
-  push:
-    branches: [ "main" ]
+  push:  # Further filtering is done in the jobs.
   pull_request:
     branches: [ "main" ]
   release:
@@ -11,6 +10,10 @@ on:
 
 jobs:
   verification:
+    if: >
+      contains(github.event.head_commit.message, '#verification') ||
+      contains(github.ref, '/main') ||
+      (github.event_name == 'pull_request')
     runs-on: ubuntu-latest
     container: ghcr.io/opencyphal/toolshed:ts22.4.3
     strategy:
@@ -64,7 +67,12 @@ jobs:
           build/*/**/*-sonarqube.xml
           build/*/**/gcovr_html/*.*
         if-no-files-found: error
+
   docs:
+    if: >
+      contains(github.event.head_commit.message, '#docs') ||
+      contains(github.ref, '/main') ||
+      (github.event_name == 'pull_request')
     runs-on: ubuntu-latest
     container: ghcr.io/opencyphal/toolshed:ts22.4.3
     steps:
@@ -101,7 +109,12 @@ jobs:
         name: pr-docs
         path: "build/suites/docs/html/"
         if-no-files-found: error
+
   sonarqube:
+    if: >
+      contains(github.event.head_commit.message, '#sonar') ||
+      contains(github.ref, '/main') ||
+      (github.event_name == 'pull_request')
     needs:
     - verification
     - docs