Install pymc from conda-forge

Author: maresb

conda-envs/environment-test.yml

@@ -1,16 +1,16 @@
 name: pymc-experimental-test
 channels:
 - conda-forge
-- defaults
+- nodefaults
 dependencies:
-- pip
+- pymc>=5.19.1
 - pytest-cov>=2.5
 - pytest>=3.0
 - dask
 - xhistogram
 - statsmodels
+- pip
 - pip:
-  - pymc>=5.19.1  # CI was failing to resolve
   - blackjax
   - scikit-learn
   - better_optimize>=0.0.10