ci: enable code coverage option

Build tests with enabled `ENABLE_COV` CMake option. Follows up
commit "cmake: fix code coverage with ENABLE_LAPI_TESTS".

Author: ligurio

.github/workflows/test.yaml

@@ -69,6 +69,7 @@ jobs:
           cmake -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ \
                 -DUSE_LUA=ON -DENABLE_BUILD_PROTOBUF=OFF \
                 -DENABLE_INTERNAL_TESTS=ON -DENABLE_LAPI_TESTS=ON \
+                -DENABLE_COV=ON \
                 -G Ninja -S . -B build
         if: ${{ matrix.LUA == 'lua' }}
 
@@ -77,6 +78,7 @@ jobs:
           cmake -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ \
                 -DUSE_LUAJIT=ON -DENABLE_BUILD_PROTOBUF=OFF \
                 -DENABLE_INTERNAL_TESTS=ON -DENABLE_LAPI_TESTS=ON \
+                -DENABLE_COV=ON \
                 -G Ninja -S . -B build
         if: ${{ matrix.LUA == 'luajit' }}