MAINT: add code of conduct

Author: KD-7

.github/CODE_OF_CONDUCT.md

@@ -0,0 +1,9 @@
+# Code of Conduct
+
+We are committed to creating a friendly and respectful place for having discussions, asking questions, and sharing ideas.
+Decisions are made by consensus and technical merit.
+
+Any contributions big or small are welcomed and appreciated. 
+Reviewing code, improving documentation, and submitting bug reports are all great ways to do this.
+
+We abide by the Python Software Foundation Code of Conduct which can be found at https://www.python.org/psf/conduct/.