Cancel running workflows automatically on PR update (#31044)

* Cancel running workflows automatically on PR update
* Add the last update later to check cancellation is working
* Use github.run_number instead of github.sha

.github/workflows/bootstrap.yml

@@ -19,6 +19,10 @@ on:
     # nightly at 2:16 AM
     - cron: '16 2 * * *'
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.run_number }}
+  cancel-in-progress: true
+
 jobs:
 
   fedora-clingo-sources:

.github/workflows/build-containers.yml

@@ -19,6 +19,10 @@ on:
   release:
     types: [published]
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.run_number }}
+  cancel-in-progress: true
+
 jobs:
   deploy-images:
     runs-on: ubuntu-latest

.github/workflows/macos_python.yml

@@ -16,6 +16,10 @@ on:
       - '.github/workflows/macos_python.yml'
       # TODO: run if we touch any of the recipes involved in this
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.run_number }}
+  cancel-in-progress: true
+
 # GitHub Action Limits
 # https://help.github.com/en/actions/reference/workflow-syntax-for-github-actions
 

.github/workflows/unit_tests.yaml

@@ -9,6 +9,11 @@ on:
     branches:
       - develop
       - releases/**
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.run_number }}
+  cancel-in-progress: true
+
 jobs:
   # Validate that the code can be run on all the Python versions
   # supported by Spack

.github/workflows/windows_python.yml

@@ -9,6 +9,11 @@ on:
     branches:
       - develop
       - releases/**
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.run_number }}
+  cancel-in-progress: true
+
 defaults:
   run:
     shell: