requirements.txt updated

Author: Arun S Kumar

requirements.txt

@@ -1,7 +1,7 @@
-coveralls==1.11.1; python_version < '3.0'
-coveralls==2.1.2; python_version > '3.0'
-flake8<3.7,>=3;
-flake8-per-file-ignores==0.8.1
+coveralls==1.11.1; python_version < '3.4'
+coveralls==2.1.2; python_version > '3.4'
+flake8==3.7.9
+flake8-per-file-ignores==0.6
 future==0.18.2
 graphene>=2.1.8,<3
 iso8601==0.1.13
@@ -11,7 +11,6 @@ mongomock==3.21.0
 pymongo==3.11.0
 pytest==4.6.11; python_version < '3.0'
 pytest==6.1.2; python_version > '3.0'
-pytest-cov==2.10.1
 singledispatch==3.4.0.3
 # https://stackoverflow.com/a/58189684/9041712
 attrs==20.2.0