pre-commit: Update requirements

Gets rid of an annoying warning about using mutable references.

Signed-off-by: Stephen Finucane <[email protected]>

.pre-commit-config.yaml

@@ -6,11 +6,11 @@ default_language_version:
   python: python3
 repos:
   - repo: https://github.com/ambv/black
-    rev: stable
+    rev: 21.10b0
     hooks:
       - id: black
   - repo: https://github.com/pre-commit/pre-commit-hooks
-    rev: v3.1.0
+    rev: v4.0.1
     hooks:
       - id: trailing-whitespace
       - id: mixed-line-ending
@@ -24,6 +24,6 @@ repos:
         files: .*\.(yaml|yml)$
       - id: check-added-large-files
   - repo: https://gitlab.com/pycqa/flake8
-    rev: 3.8.3
+    rev: 3.9.2
     hooks:
       - id: flake8