Use concurrency groups to limit duplicate jobs

Leverage concurrency groups along with cancel-in-progress to favor running the most recent job.

Concurrency groups are on a per workflow, per branch/tag basis. So, pushing newer updates to a branch, e.g. as part of a PR, should cancel any in progress runs of workflows that have been retriggered.

See:
- https://docs.github.com/en/enterprise-cloud@latest/actions/using-workflows/workflow-syntax-for-github-actions#concurrency
- https://docs.github.com/en/enterprise-cloud@latest/actions/learn-github-actions/contexts#github-context

.github/workflows/checks.yml

@@ -1,6 +1,10 @@
 name: Checks
 on: [push, pull_request]
 
+concurrency:
+  group: ${{github.workflow}}-${{ github.ref }}
+  cancel-in-progress: true
+
 jobs:
   checks:
     runs-on: ubuntu-latest

.github/workflows/publish.yml

@@ -4,6 +4,10 @@ on:
     tags:
       - '[0-9]+.[0-9]+.[0-9]+'
 
+concurrency:
+  group: ${{github.workflow}}-${{ github.ref }}
+  cancel-in-progress: true
+
 jobs:
   publish:
     runs-on: ubuntu-latest

.github/workflows/tests-macos.yml

@@ -1,6 +1,10 @@
 name: macOS
 on: [push, pull_request]
 
+concurrency:
+  group: ${{github.workflow}}-${{ github.ref }}
+  cancel-in-progress: true
+
 jobs:
   tests:
     runs-on: macos-11

.github/workflows/tests-ubuntu.yml

@@ -1,6 +1,10 @@
 name: Ubuntu
 on: [push, pull_request]
 
+concurrency:
+  group: ${{github.workflow}}-${{ github.ref }}
+  cancel-in-progress: true
+
 jobs:
   tests:
     runs-on: ubuntu-latest

.github/workflows/tests-windows.yml

@@ -1,6 +1,10 @@
 name: Windows
 on: [push, pull_request]
 
+concurrency:
+  group: ${{github.workflow}}-${{ github.ref }}
+  cancel-in-progress: true
+
 jobs:
   tests:
     runs-on: windows-latest