Testing on all latest runner OSes (windows is YOLO test)

Author: reactive-firewall

.github/workflows/shellcheck.yml

@@ -10,7 +10,16 @@ jobs:
       pull-requests: read  # to get PR metadata
       security-events: write  # for github/codeql-action/upload-sarif to upload SARIF results
     name: ShellCheck Analysis
-    runs-on: macos-latest
+    runs-on: ${{ matrix.os }}
+    defaults:
+      run:
+        shell: bash
+    timeout-minutes: 10
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macos-latest, windows-latest]
+    env:
+      OS: ${{ matrix.os }}
     steps:
       - name: Checkout repository
         uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2