Bump numpy from 1.18.1 to 1.19.1

Bumps [numpy](https://github.com/numpy/numpy) from 1.18.1 to 1.19.1.
- [Release notes](https://github.com/numpy/numpy/releases)
- [Changelog](https://github.com/numpy/numpy/blob/master/doc/HOWTO_RELEASE.rst.txt)
- [Commits](https://github.com/numpy/numpy/compare/v1.18.1...v1.19.1)

requirements.txt

@@ -10,7 +10,7 @@ matplotlib==3.1.3
 mlxtend==0.17.2
 more-itertools==8.2.0
 numba==0.48.0
-numpy==1.18.1
+numpy==1.19.1
 outlier==0.2
 utils==1.0.1
 outlier-utils==0.0.3