Reduce CI build matrix on macOS/Windows and add concurrency groups

.github/workflows/build.yml

@@ -4,13 +4,21 @@ on:
   push:
     branches: [ 'sustaining/5.4.x','master', 'issues/**', 'features/**' ]
   pull_request:
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
 jobs:
   build-maven:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
+        os: [ 'ubuntu-latest' ]
         java: [ '11', '17', '21', '25', '26' ]
-        os: [ 'ubuntu-latest', 'macos-latest', 'windows-latest' ]
+        include:
+          - { os: 'macos-latest',   java: '11' }
+          - { os: 'macos-latest',   java: '26' }
+          - { os: 'windows-latest', java: '11' }
+          - { os: 'windows-latest', java: '26' }
       fail-fast: false
     steps:
     - uses: actions/checkout@v6

.github/workflows/deploy.yml

@@ -6,6 +6,9 @@ on:
     branches: [ 'sustaining/5.4.x','master' ]
     workflows: ["Build","Release"]
     types: [completed]
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.workflow_run.head_branch }}
+  cancel-in-progress: false
 jobs:
   deploy-maven:
     if: ${{ github.event.workflow_run.conclusion == 'success'  && github.event.workflow_run.event=='push' }}

.github/workflows/release.yml

@@ -11,6 +11,9 @@ on:
         description: "Default version to use for new local working copy."
         required: true
         default: "X.Y.Z-SNAPSHOT"
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: false
 jobs:
   release-maven:
     runs-on: 'ubuntu-latest'