Add a badge in README to represent the type of COC (#105)

README.md

@@ -14,6 +14,7 @@ PyVista accessors for Gmsh to generate 3D finite element mesh.
 [![pre-commit.ci status](https://results.pre-commit.ci/badge/github/pyvista/pvgmsh/main.svg)](https://results.pre-commit.ci/latest/github/pyvista/pvgmsh/main)
 [![NEP29](https://raster.shields.io/badge/follows-NEP29-orange.png)](https://numpy.org/neps/nep-0029-deprecation_policy.html)
 [![License: GPL v3](https://img.shields.io/badge/License-GPLv3-blue.svg)](https://www.gnu.org/licenses/gpl-3.0)
+[![Contributor Covenant](https://img.shields.io/badge/contributor%20covenant-2.1-4baaaa.svg)](https://github.com/bjlittle/geovista/blob/main/CODE_OF_CONDUCT.md)
 
 ## Motivation