update requirements to include compatible versions

Author: brandonmoser

requirements.txt

@@ -1,9 +1,9 @@
-arrow==0.12.1
-backports.functools-lru-cache==1.5
-certifi==2018.4.16
-chardet==3.0.4
-idna==2.6
-python-dateutil==2.7.3
-requests==2.20.1
-six==1.11.0
-urllib3==1.22
+arrow~=0.12.1
+backports.functools-lru-cache~=1.5
+certifi~=2018.4.16
+chardet~=3.0.4
+idna~=2.6
+python-dateutil~=2.7.3
+requests~=2.20.1
+six~=1.14.0
+urllib3~=1.22