Instead of "latest" use more precise labels for GitHub-hosted runners

This fixes the build failure caused by the update of
`macos-latest` to macOS 14 ARM64
(actions/runner-images@da5ebb3)
whereas UI tests currently can't be executed on ARM64.

.github/workflows/ci.yml

@@ -7,8 +7,8 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu, windows, macos]
-    runs-on: ${{ matrix.os }}-latest
+        os: [ubuntu-22.04, windows-2022, macos-13]
+    runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
       - uses: actions/setup-java@99b8673ff64fbf99d8d325f52d9a5bdedb8483e9 # v4.2.1