pre-commit: Bump versions

Also skip installation in pep8 job to speed up the check.

Change-Id: I90b13eef56cea666d7d3a13e3ea63f9dc9830ca8

.pre-commit-config.yaml

@@ -1,6 +1,6 @@
 repos:
   - repo: https://github.com/pre-commit/pre-commit-hooks
-    rev: v4.5.0
+    rev: v5.0.0
     hooks:
       - id: trailing-whitespace
       # Replaces or checks mixed line ending
@@ -24,7 +24,7 @@ repos:
       - id: hacking
         additional_dependencies: []
   - repo: https://github.com/asottile/pyupgrade
-    rev: v3.18.0
+    rev: v3.19.1
     hooks:
       - id: pyupgrade
         args: [--py3-only]

tox.ini

@@ -22,6 +22,7 @@ commands =
   stestr slowest
 
 [testenv:pep8]
+skip_install = true
 deps =
   pre-commit>=2.6.0 # MIT
 commands =