ci: install firefox on macos-latest

.github/workflows/test.yml

@@ -21,7 +21,7 @@ jobs:
             os: ubuntu-latest
             rust: stable
           - build: macos-stable
-            os: macos-13
+            os: macos-latest
             rust: stable
           - build: windows-stable
             os: windows-latest
@@ -30,6 +30,8 @@ jobs:
     steps:
       - uses: actions/checkout@v3
       - uses: nanasess/setup-chromedriver@master
+      - if: matrix.os == 'macos-latest'
+        run: brew install --cask firefox
       - uses: dtolnay/rust-toolchain@stable
         with:
           toolchain: ${{ matrix.rust }}