fix: try to speed-up build

Author: bednar

.travis.yml

@@ -1,12 +1,12 @@
 language: python
 
 python:
-  - "2.7"
-  - "3.5"
-  - "3.6"
-  - "3.7"
+#  - "2.7"
+#  - "3.5"
+#  - "3.6"
+#  - "3.7"
   - "3.8"
-  - "3.9"
+  - "3.9-dev"
   - "pypy"
   - "pypy3"
 

tox.ini

@@ -15,7 +15,7 @@ deps = -r{toxinidir}/requirements.txt
        py37: pandas==0.24.2
        py37: numpy==1.16.2
        py38: pandas==0.24.2
-       py38: numpy==1.16.2
+       py38: numpy==1.17.2
        py39: pandas==0.24.2
        py39: numpy==1.16.2
 # Only install pandas with non-pypy interpreters