update CI and cov badges

README.md

@@ -1,7 +1,7 @@
 # splot
 
-[![Build Status](https://travis-ci.org/pysal/splot.svg?branch=master)](https://travis-ci.org/pysal/splot)
-[![Coverage Status](https://coveralls.io/repos/github/pysal/splot/badge.svg?branch=master)](https://coveralls.io/github/pysal/splot?branch=master)
+[![unittests](https://github.com/pysal/splot/workflows/.github/workflows/unittests.yml/badge.svg)](https://github.com/pysal/splot/actions?query=workflow%3A.github%2Fworkflows%2Funittests.yml)
+[![codecov](https://codecov.io/gh/pysal/splot/branch/main/graph/badge.svg)](https://codecov.io/gh/pysal/splot)
 [![Documentation Status](https://readthedocs.org/projects/splot/badge/?version=latest)](https://splot.readthedocs.io/en/latest/?badge=latest)
 [![PyPI version](https://badge.fury.io/py/splot.svg)](https://badge.fury.io/py/splot)
 [![DOI](https://joss.theoj.org/papers/10.21105/joss.01882/status.svg)](https://doi.org/10.21105/joss.01882)