Remove upper boundaries from requirements

This to allow to use the higher versions to resolve possible conflicts when used in combinatin with other libs who need the higher versions.

requirements.txt

@@ -1,9 +1,9 @@
-requests>=0.10,<3.0.0
-six>=1.0.0,<2.0.0
-wheel==0.30.0
-boto==2.48.0
-python-dateutil>=2.6.1,<3.0.0
-diskcache>=2.9.0,<3.0.0
+requests>=0.10
+six>=1.0.0
+wheel>=0.30.0
+boto>=2.48.0
+python-dateutil>=2.6.1
+diskcache>=2.9.0
 setuptools>=39.0.1
-attrs>=18.1.0,<19.0.0
-trans>=2.1.0,<3.0.0
+attrs>=18.1.0
+trans>=2.1.0