Include GH action for Java 21

.github/workflows/java21.yaml

@@ -0,0 +1,17 @@
+name: Java 21
+on:
+  - push
+  - workflow_dispatch
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Set up Azul JDK 21
+        uses: actions/setup-java@v3
+        with:
+          java-version: 21
+          distribution: 'zulu'
+          cache: 'maven'
+      - name: Test in Maven
+        run: mvn --no-transfer-progress -B test

.github/workflows/macos-x64.yaml

@@ -4,7 +4,7 @@ on:
   - workflow_dispatch
 jobs:
   build:
-    runs-on: macos-11
+    runs-on: macos-latest
     steps:
       - uses: actions/checkout@v3
       - name: Set up Azul JDK 11

README.md

@@ -5,6 +5,7 @@
 [![Java 8](https://img.shields.io/github/actions/workflow/status/fizzed/bigmap/java8.yaml?branch=master&label=Java%208&style=flat-square)](https://github.com/fizzed/bigmap/actions/workflows/java8.yaml)
 [![Java 11](https://img.shields.io/github/actions/workflow/status/fizzed/bigmap/java11.yaml?branch=master&label=Java%2011&style=flat-square)](https://github.com/fizzed/bigmap/actions/workflows/java11.yaml)
 [![Java 17](https://img.shields.io/github/actions/workflow/status/fizzed/bigmap/java17.yaml?branch=master&label=Java%2017&style=flat-square)](https://github.com/fizzed/bigmap/actions/workflows/java17.yaml)
+[![Java 21](https://img.shields.io/github/actions/workflow/status/fizzed/bigmap/java21.yaml?branch=master&label=Java%2021&style=flat-square)](https://github.com/fizzed/bigmap/actions/workflows/java21.yaml)
 
 [![Linux x64](https://img.shields.io/github/actions/workflow/status/fizzed/bigmap/java11.yaml?branch=master&label=Linux%20x64&style=flat-square)](https://github.com/fizzed/bigmap/actions/workflows/java11.yaml)
 [![MacOS x64](https://img.shields.io/github/actions/workflow/status/fizzed/bigmap/macos-x64.yaml?branch=master&label=MacOS%20x64&style=flat-square)](https://github.com/fizzed/bigmap/actions/workflows/macos-x64.yaml)