Un-pin mypy version and update

I submitted some fixes to the bleach stubs and those have been released
in typeshed now, so the mypy version can be safely updated again.

tildes/requirements-to-freeze.txt

@@ -10,7 +10,7 @@ freezegun
 gunicorn
 html5lib
 ipython
-mypy==0.670  # 0.700 includes incorrect bleach stubs
+mypy
 mypy-extensions
 Pillow
 prometheus-client

tildes/requirements.txt

@@ -34,7 +34,7 @@ MarkupSafe==1.1.1
 marshmallow==2.19.5
 mccabe==0.6.1
 more-itertools==7.0.0
-mypy==0.670
+mypy==0.710
 mypy-extensions==0.4.1
 packaging==19.0
 parso==0.5.0
@@ -100,7 +100,7 @@ toml==0.10.0
 traitlets==4.3.2
 transaction==2.4.0
 translationstring==1.3
-typed-ast==1.3.5
+typed-ast==1.4.0
 urllib3==1.25.3
 venusian==1.2.0
 waitress==1.3.0