Fix BSK tests (#126)

* Update BSK tests

* Get xcode version from dotfile

* Update test.yml

* Bring back cache step

.github/workflows/test.yml

@@ -73,6 +73,7 @@ jobs:
         with:
           repository: 'duckduckgo/BrowserServicesKit'
           path: 'BrowserServicesKit'
+          submodules: recursive
       - name: Check out the tests
         uses: actions/checkout@v3
         with:
@@ -98,7 +99,7 @@ jobs:
             ${{ runner.os }}-spm-
 
       - name: Select Xcode
-        run: sudo xcode-select -s /Applications/Xcode_15.0.app/Contents/Developer
+        run: sudo xcode-select -s /Applications/Xcode_$(<BrowserServicesKit/.xcode-version).app/Contents/Developer
 
       - name: Install xcbeautify
         continue-on-error: true