CI: Cancel stale workflows when new commits are added to a PR

Author: callumfare

.github/workflows/cmake.yml

@@ -2,6 +2,10 @@ name: Build and test
 
 on: [push, pull_request]
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
 jobs:
   ubuntu-build:
     name: Build - Ubuntu

.github/workflows/codeql.yml

@@ -2,6 +2,10 @@ name: "CodeQL"
 
 on: [push, pull_request]
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
 jobs:
   analyze-ubuntu:
     name: Analyze on Ubuntu