Extra py36 cleanup

Author: maxiberta

requirements.docs.txt

@@ -1,3 +1,3 @@
-Sphinx==7.0.1;python_version>"3.6"
+Sphinx==7.0.1
 werkzeug
 setuptools<=81  # pkg_resources was removed from setuptools 82

requirements.tests.txt

@@ -1,7 +1,7 @@
 # these are pinned for repeatability, but updated by pyup.io to be latest
 pytest==4.6.9;python_version<"3.10"
 pytest>7;python_version>="3.10"
-more-itertools;python_version>="3.6"
+more-itertools
 freezegun==0.3.14
 pytest-cov==2.8.1;python_version<"3.10"
 pytest-cov>2.8;python_version>="3.10"
@@ -15,7 +15,7 @@ setuptools==44.0.0;python_version<"3.10"
 setuptools>64,<=81;python_version>="3.10"
 coverage==5.0.3;python_version<"3.10"
 coverage>=6.0;python_version>="3.10"
-flaky==3.8.1;python_version>="3.6"
+flaky==3.8.1
 
 # for integration tests
 # eventlet is pinned until https://github.com/benoitc/gunicorn/pull/2581