install dateutil from master

Author: jreback

ci/requirements-3.6_NUMPY_DEV.build.sh

@@ -10,6 +10,8 @@ pip uninstall numpy -y
 # install numpy wheel from master
 PRE_WHEELS="https://7933911d6844c6c53a7d-47bd50c35cd79bd838daf386af554a83.ssl.cf2.rackcdn.com"
 pip install --pre --upgrade --timeout=60 -f $PRE_WHEELS numpy scipy
-pip install -U git+git://github.com/dateutil/dateutil.git@33614e72c4beecae4821eb4012d6cb13c1bac585
+
+# install dateutil from master
+pip install -U git+git://github.com/dateutil/dateutil.git
 
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