Minimal conda dependency set

Hopefully this gets conda working again...

.appveyor.yml

@@ -36,13 +36,7 @@ build_script:
   - SET PATH=C:\Py;C:\Py\Scripts;C:\Py\Library\bin;%PATH%
   - conda config --set always_yes yes
   - conda update conda
-# Pinning pillow==5.4.1 as version 6 breaks on current latest reportlab
-# https://bitbucket.org/rptlab/reportlab/issues/176/incompatibility-with-pillow-600
-  - conda install setuptools numpy psycopg2 matplotlib networkx reportlab scipy coverage pillow==5.4.1
-
-# Pinning mysql-connector-python==8.0.13 for Python 3 as 8.0.16 breaks our tests
-# https://github.com/biopython/biopython/issues/2120
-  - conda install mysql-connector-python==8.0.13
+  - conda install coverage setuptools numpy
   - python setup.py build
 
 test_script: