Cancel CI jobs when newer HEAD commit available.

.github/workflows/build.yml

@@ -1,5 +1,8 @@
 name: Build
 on: [push, pull_request]
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
 jobs:
   ci:
     name: ${{ matrix.name }}

.github/workflows/codeql.yml

@@ -4,6 +4,9 @@ on:
   pull_request:
   schedule:
     - cron: '0 1 * * 4'
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
 jobs:
   analyze:
     name: Analyze

.github/workflows/fuzz.yml

@@ -1,5 +1,8 @@
 name: OSS-Fuzz
 on: [pull_request]
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
 jobs:
   Fuzzing:
     runs-on: ubuntu-latest