Allow black and rst pre-commit hooks to run on any Python 3 version

Since py2 is dropped we don't really need to worry about this anymore.

Author: bluetech

.pre-commit-config.yaml

@@ -4,7 +4,6 @@ repos:
     hooks:
     -   id: black
         args: [--safe, --quiet, --target-version, py35]
-        language_version: python3.7
 -   repo: https://github.com/pre-commit/pre-commit-hooks
     rev: v4.0.1
     hooks:
@@ -29,4 +28,3 @@ repos:
         files: ^(CHANGELOG.rst|HOWTORELEASE.rst|README.rst|changelog/.*)$
         language: python
         additional_dependencies: [pygments, restructuredtext_lint]
-        language_version: python3.7