Try to fix codecov (#3946)

Update the main workflow to use the GitHub Action version of `codecov` instead of the bash version.

.github/workflows/main.yml

@@ -317,11 +317,18 @@ jobs:
       - name: Run themes tests
         run: cd "${{ github.workspace }}/build" && make check-themes
 
-      - name: Upload Lua code coverage report
+      - name: Generate Lua coverage report
         if: matrix.coverage == 'codecov'
         run: |
           luacov
-          bash /tmp/codecov-bash -f build/luacov.report.out -X gcov -X coveragepy -F luacov
+
+      - name: Upload Lua code coverage report
+        if: matrix.coverage == 'codecov'
+        uses: codecov/codecov-action@v3
+        with:
+          files: "${{ github.workspace }}/build/luacov.report.out"
+        env:
+          CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
 
       - name: Upload C code coverage report
         if: matrix.coverage == 'codecov'