add markers to backports

Author: Kilo59

Pipfile

@@ -10,7 +10,7 @@ asyncmock = "*"
 bandit = "*"
 black = "==19.10b0"
 coveralls = "*"
-importlib-metadata = "*"
+importlib-metadata = {version="*", markers="python_version<'3.8'"}
 invoke = "*"
 isort = "*"
 pylint = "*"
@@ -22,10 +22,10 @@ pytest-cov = "*"
 aiohttp = "*"
 asyncache = "*"
 cachetools = "*"
-dataclasses = "*"
+dataclasses = {version="*", markers="python_version<'3.7'"}
 fastapi = "*"
 gunicorn = "*"
-idna_ssl = "*"
+idna_ssl = {version="*", markers="python_version<'3.7'"}
 python-dateutil = "*"
 python-dotenv = "*"
 requests = "*"