Automatic merge from submit-queue (batch tested with PRs 44337, 45775, 45832, 45574, 45758)

Fix lint failures on kubernetes-e2e charm

**What this PR does / why we need it**:

This fixes a test failure on the kubernetes-e2e charm relating to tox and flake8:

```DEBUG:runner:/bin/sh: 1: flake8: not found```

**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #

**Special notes for your reviewer**:

This is a follow-up to https://github.com/kubernetes/kubernetes/pull/45494 where the same thing was done for kubernetes-master.

**Release note**:

```release-note
Fix lint failures on kubernetes-e2e charm
```