fix(requirements): pytest version for python3.7 and higher (#396)

Author: maorlx

requirements-dev.txt

@@ -7,7 +7,8 @@ Flask
 pylint>=1.9.5,<=2.5.3
 pylint-quotes
 django
-pytest==6.0.0; python_version >= '3.5'
+pytest==6.2.5; python_version >= '3.7'
+pytest==6.0.0; python_version >= '3.5' and python_version < '3.7'
 pytest==4.6.0; python_version < '3.5'
 requests
 sqlalchemy==1.3.23