tsutterley/pyTMD: v2.0.6

Summary: This a relatively minor release that includes some bug fixes and performance improvements.

Itemized Changes:

• feat: improve conversion of timescale to datetime arrays #220
• docs: update graphviz fonts to match overall readthedocs style #220
• refactor: switch from import warnings to debug logging #220
• fix: output constituents from get and pop as copies to keep original data immutable #222

Full Changelog: https://github.com/tsutterley/pyTMD/compare/2.0.5...2.0.6