Add codecov for code coverage (#5)

* Add codecov for code coverage

Author: eriknw

.github/workflows/test.yml

@@ -30,7 +30,8 @@ jobs:
           activate-environment: testing
       - name: Install dependencies
         run: |
-          conda install -c conda-forge python-graphblas networkx scipy pytest coverage black flake8 coveralls
+          conda install -c conda-forge python-graphblas networkx scipy \
+            pytest coverage black flake8 flake8-comprehensions flake8-bugbear
           pip install -e .
       - name: Style checks
         run: |
@@ -39,33 +40,6 @@ jobs:
       - name: PyTest
         run: |
           coverage run --branch -m pytest
+          coverage xml
       - name: Coverage
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-          COVERALLS_FLAG_NAME: ${{ matrix.python-version}}/${{ matrix.os }}
-          COVERALLS_PARALLEL: true
-        run: |
-          coverage report --show-missing
-          # coveralls --service=github  # Broken :(
-
-#  finish:
-#    needs: test
-#    if: always()
-#    runs-on: ubuntu-latest
-#    defaults:
-#      run:
-#        shell: bash -l {0}
-#    steps:
-#      - name: Create env
-#        uses: conda-incubator/setup-miniconda@v2
-#        with:
-#          auto-update-conda: true
-#          python-version: "3.10"
-#          activate-environment: finishing
-#      - name: Update env
-#        run: conda install -c conda-forge coveralls
-#      - name: Coveralls finished
-#        env:
-#          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-#        run: |
-#          coveralls --finish
+        uses: codecov/codecov-action@v2

README.md

@@ -3,7 +3,7 @@
 [![pypi](https://img.shields.io/pypi/v/graphblas-algorithms.svg)](https://pypi.python.org/pypi/graphblas-algorithms/)
 [![License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://github.com/python-graphblas/graphblas-algorithms/blob/main/LICENSE)
 [![Tests](https://github.com/python-graphblas/graphblas-algorithms/workflows/Tests/badge.svg?branch=main)](https://github.com/python-graphblas/graphblas-algorithms/actions)
-<!--- [![Coverage](https://coveralls.io/repos/python-graphblas/graphblas-algorithms/badge.svg?branch=main)](https://coveralls.io/r/python-graphblas/graphblas-algorithms) --->
+[![Coverage](https://codecov.io/gh/python-graphblas/graphblas-algorithms/branch/main/graph/badge.svg)](https://codecov.io/gh/python-graphblas/graphblas-algorithms)
 <!--- [![conda-forge](https://img.shields.io/conda/vn/conda-forge/graphblas-algorithms.svg)](https://anaconda.org/conda-forge/graphblas-algorithms) --->
 <!--- [![Docs](https://readthedocs.org/projects/graphblas-algorithms/badge/?version=latest)](https://graphblas-algorithms.readthedocs.io/en/latest/) --->