Try to allow newer requirements versions

Author: Carl Vitzthum

requirements.txt

@@ -1,10 +1,10 @@
-boto3==1.4.1
-botocore==1.4.61
-click==6.6
-docutils==0.12
-futures==3.0.5
-jmespath==0.9.0
-pyaml==15.8.2
-python-dateutil==2.5.3
-PyYAML==3.11
-six==1.10.0
+boto3>=1.4.1
+botocore>=1.4.61
+click>=6.6
+docutils>=0.12
+futures>=3.0.5
+jmespath>=0.9.0
+pyaml>=15.8.2
+python-dateutil>=2.5.3
+PyYAML>=3.11
+six>=1.10.0