fix: try to speed-up build

Author: bednar

tox.ini

@@ -16,7 +16,7 @@ deps = -r{toxinidir}/requirements.txt
        py37: numpy==1.16.2
        py38: pandas==1.1.2
        py38: numpy==1.19.0
-       py39: pandas==1.1.2
+       py39: pandas==1.1.3
        py39: numpy==1.19.2
 # Only install pandas with non-pypy interpreters
 # Testing all combinations would be too expensive