Add Conda Downloads Badge

Author: PatriceJada

README.rst

@@ -3,7 +3,7 @@
     :alt: PyMC logo
     :align: center
 
-|Build Status| |Coverage| |NumFOCUS_badge| |Binder| |Dockerhub| |DOIzenodo|
+|Build Status| |Coverage| |NumFOCUS_badge| |Binder| |Dockerhub| |DOIzenodo| |Conda Downloads|
 
 PyMC (formerly PyMC3) is a Python package for Bayesian statistical modeling
 focusing on advanced Markov chain Monte Carlo (MCMC) and variational inference (VI)
@@ -314,3 +314,5 @@ Thanks to our contributors
    :target: https://odsc.com/california/?utm_source=pymc&utm_medium=referral
 .. |contributors| image:: https://contrib.rocks/image?repo=pymc-devs/pymc
    :target: https://github.com/pymc-devs/pymc/graphs/contributors
+.. |Conda Downloads| image:: https://anaconda.org/conda-forge/pymc/badges/downloads.svg
+   :target: https://anaconda.org/conda-forge/pymc