Build and test with Node.js 26 as well

Author: robtimus

.github/workflows/build.yml

@@ -26,7 +26,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        node: ['18', '20', '22', '24']
+        node: ['18', '20', '22', '24', '26']
       fail-fast: false
     steps:
       - uses: actions/checkout@v6