Bump numpy from 1.13.3 to 1.15.4

Bumps [numpy](http://www.numpy.org) from 1.13.3 to 1.15.4.

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot-support

Pipfile

@@ -12,7 +12,7 @@ certifi = "==2017.11.5"
 chardet = "==3.0.4"
 docopt = "==0.6.2"
 idna = "==2.6"
-numpy = "==1.13.3"
+numpy = "==1.15.4"
 requests = "==2.20.1"
 scikit-learn = "==0.19.1"
 scipy = "==1.0.0"