BB2-3573: Update flake8 to match our CI checks

[jimmyfagan]

JIRA Ticket:
BB2-3573

What Does This PR Do?

Updates our flake8 version to match the version used in our CI checks.

What Should Reviewers Watch For?

If you're reviewing this PR, please check for these things in particular:
Does the pre-commit still work locally?

Validation

1. On master, in openid.py, line 119, replace del (data with del(data and save the file
2. Try to commit with git commit -a
3. Confirm that flake8 didn't give any errors (though don't enter a commit message and allow the commit to fail since you don't want to commit that)
4. Repeat the same steps on this branch, and confirm that the commit fails due to no whitespace after del in the line you edited.

What Security Implications Does This PR Have?

Please indicate if this PR does any of the following:

• Adds any new software dependencies
• Modifies any security controls
• Adds new transmission or storage of data
• Any other changes that could possibly affect security?

• Yes, one or more of the above security implications apply. This PR must not be merged without the ISSO or team
  security engineer's approval.

Any Migrations?

• Yes, there are migrations
  • The migrations should be run PRIOR to the code being deployed
  • The migrations should be run AFTER the code is deployed
  • There is a more complicated migration plan (downtime,
    etc)
• No migrations