[GitHub Actions] Run Codecov on Xcode 11.7

.github/workflows/xcodebuild.yml

@@ -44,6 +44,6 @@ jobs:
         run: xcodebuild ${{ matrix.xcode_flags_for_build_only }} -sdk watchsimulator | xcpretty
         shell: bash
       - name: Codecov
-        if: matrix.xcode_version == '12'
+        if: matrix.xcode_version == '11.7'
         run: curl -s https://codecov.io/bash | bash -s -- -t ${{ secrets.CODECOV_TOKEN }}
         shell: bash