Enable on-demand GitHub Actions workflows

.github/workflows/build-images.yml

@@ -15,6 +15,10 @@ on:
   pull_request:
     types: [opened, synchronize]
 
+  # Allow workflow to be triggered manually.
+  # https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows
+  workflow_dispatch:
+
 jobs:
   build_stable_image_using_makefile:
     name: Build stable image using Makefile

.github/workflows/project-analysis.yml

@@ -13,6 +13,10 @@ on:
     # (whether force-pushed or not)
     types: [opened, synchronize]
 
+  # Allow workflow to be triggered manually.
+  # https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows
+  workflow_dispatch:
+
 jobs:
   lint:
     name: Lint

.github/workflows/scheduled-monthly.yml

@@ -15,6 +15,10 @@ on:
     # * * * * *
     - cron: "30 4 1 * *"
 
+  # Allow workflow to be triggered manually.
+  # https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows
+  workflow_dispatch:
+
 jobs:
   build_all_images_using_makefile:
     name: Build all images using Makefile

.github/workflows/scheduled-weekly.yml

@@ -15,6 +15,10 @@ on:
     # * * * * *
     - cron: "30 4 * * 0"
 
+  # Allow workflow to be triggered manually.
+  # https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows
+  workflow_dispatch:
+
 jobs:
   lint:
     name: Lint