docs: badges: show code quality via LGTM.com
It gives us an A, so we can link there :).
`gnpy`: mesh optical network route planning and optimization library
====================================================================
-|docs| |travis| |doi| |contributors|
+|docs| |travis| |doi| |contributors| |codacy-quality|
**`gnpy` is an open-source, community-developed library for building route
planning and optimization tools in real-world mesh optical networks.**
@@ -222,6 +222,11 @@ implementations.
:alt: Code Contributors via GitHub
:scale: 100%
+.. |codacy-quality| image:: https://img.shields.io/lgtm/grade/python/github/Telecominfraproject/oopt-gnpy
+ :target: https://lgtm.com/projects/g/Telecominfraproject/oopt-gnpy/
+ :alt: Code Quality via LGTM.com
+ :scale: 100%
+
TIP OOPT/PSE & PSE WG Charter
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