setup codecov for C++ and Fortran files in PyPartMC src folder

.github/workflows/codecov.yml

@@ -0,0 +1,27 @@
+name: codecov
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+      branches: [ main ]
+
+jobs:
+  codecov:
+    runs-on: ubuntu-22.04
+    steps:
+      - uses: actions/checkout@v4.2.2
+        with:
+          submodules: recursive
+          fetch-depth: 0
+      - run: sudo apt install -y lcov
+      - run: |
+          set -xe
+          CMAKE_ARGS="-DCMAKE_CXX_FLAGS=--coverage -DCMAKE_C_FLAGS=--coverage -DCMAKE_Fortran_FLAGS=--coverage" pip install -e .[tests]
+          pytest -We tests
+          lcov --capture --directory ./build/*/_PyPartMC/CMakeFiles/_PyPartMC.dir/ --output-file coverage.info --no-external
+      - run: find -name \*.gcno | grep -v pypartmc.cpp | grep -v _PyPartMC.dir | xargs rm
+      - uses: codecov/codecov-action@v5.3.1
+        with:
+          token: ${{ secrets.CODECOV_TOKEN }}
+          fail_ci_if_error: true

README.md

@@ -17,6 +17,7 @@ If interested in contributing to PyPartMC, please have a look a the [notes for d
 [![Copyright](https://img.shields.io/static/v1?label=Copyright&color=249fe2&message=UIUC&)](https://atmos.illinois.edu/)
 [![Github Actions Build Status](https://github.com/open-atmos/PyPartMC/workflows/tests+pypi/badge.svg?branch=main)](https://github.com/open-atmos/PyPartMC/actions)
 [![API docs](https://shields.mitmproxy.org/badge/docs-pdoc.dev-brightgreen.svg)](https://open-atmos.github.io/PyPartMC/)
+[![codecov](https://codecov.io/gh/open-atmos/PyPartMC/graph/badge.svg?token=27IK9ZIQXE)](https://codecov.io/gh/open-atmos/PyPartMC)
 [![DOI](https://zenodo.org/badge/DOI/10.5281/zenodo.7662635.svg)](https://doi.org/10.5281/zenodo.7662635)
 [![PyPI version](https://badge.fury.io/py/PyPartMC.svg)](https://pypi.org/p/PyPartMC)