ci: add missing codecov step

Author: MilesCranmer

.github/workflows/CI.yml

@@ -54,12 +54,11 @@ jobs:
             julia --color=yes --threads=auto --check-bounds=yes --depwarn=yes --code-coverage=user -e 'import Coverage; import Pkg; Pkg.activate("."); Pkg.test(coverage=true)'
             julia --color=yes coverage.jl
         shell: bash
-      - name: Coveralls
-        uses: coverallsapp/github-action@v2
+      - uses: codecov/codecov-action@v5
         with:
-          parallel: true
-          path-to-lcov: lcov.info
-          flag-name: julia-${{ matrix.julia-version }}-${{ matrix.os }}-main-${{ github.event_name }}
+          token: ${{ secrets.CODECOV_TOKEN }}
+          files: lcov.info
+
 
   additional_tests:
     name: test ${{ matrix.test_name }} - ${{ matrix.os }}