Upgrade maximum h11 dependency version to 0.10 (#772)

The h11 Changelog for 0.10 only include those items:
 - Drop support for Python 3.4.
 - Support Python 3.8.
 - Make error messages returned by match failures less ambiguous (#98).

setup.py

@@ -45,7 +45,7 @@ def get_packages(package):
 
 minimal_requirements = [
     "click==7.*",
-    "h11>=0.8,<0.10",
+    "h11>=0.8,<0.11",
     "typing-extensions;" + env_marker_below_38,
 ]