Bump flake8 from 2.2.2 to 3.7.9#22

Bumps [flake8](https://gitlab.com/pycqa/flake8) from 2.2.2 to 3.7.9. <details> <summary>Commits</summary> <ul> <li><a href="https://gitlab.com/pycqa/flake8/commit/ee2920d775df18481d638c2da084d229d56f95b9"><code>ee2920d</code></a> Release 3.7.9</li> <li><a href="https://gitlab.com/pycqa/flake8/commit/182cdf6c23a711af32b2dbd040dd89808f5b1d18"><code>182cdf6</code></a> Merge branch 'backport_pr_340' into '3.7-maintenance'</li> <li><a href="https://gitlab.com/pycqa/flake8/commit/04d3f9dcafcc8fe3eabf66ba13b999c2e5b38f60"><code>04d3f9d</code></a> Fix travis-ci</li> <li><a href="https://gitlab.com/pycqa/flake8/commit/ee740f4a92b2856e7c62f12c37abd6f8b9b987ff"><code>ee740f4</code></a> Merge branch 'backport_pr_366' into '3.7-maintenance'</li> <li><a href="https://gitlab.com/pycqa/flake8/commit/04f49a7a777c3ceb14b8e8d5b52b12366f84f9a7"><code>04f49a7</code></a> Only use multiprocessing when the method is fork</li> <li><a href="https://gitlab.com/pycqa/flake8/commit/aa792d2930b8f6dada3f6305e8a3704d2d191005"><code>aa792d2</code></a> Release 3.7.8</li> <li><a href="https://gitlab.com/pycqa/flake8/commit/f41e87bf375e5b7b6452f6ec353543fde5a3d653"><code>f41e87b</code></a> Merge branch 'pyflake-normalize-path' into 'master'</li> <li><a href="https://gitlab.com/pycqa/flake8/commit/24e8b8163c27c9b5f9785e064f72c49232a98ac3"><code>24e8b81</code></a> pyflakes: Change to <code>normalize_path()</code> for filename normalization</li> <li><a href="https://gitlab.com/pycqa/flake8/commit/d6bf438e44152be00c840a8c3cf9a73bc2503a29"><code>d6bf438</code></a> Merge branch 'fix_linters' into 'master'</li> <li><a href="https://gitlab.com/pycqa/flake8/commit/7506847c9abaef5ff069a9bd38cd3308a3a45113"><code>7506847</code></a> fix CI build</li> <li>Additional commits viewable in <a href="https://gitlab.com/pycqa/flake8/compare/2.2.2...3.7.9">compare view</a></li> </ul> </details> <br /> [](https://dependabot.com/compatibility-score/?dependency-name=flake8&package-manager=pip&previous-version=2.2.2&new-version=3.7.9) Dependabot will resolve any conflicts with this PR as long as you don't alter it yourself. You can also trigger a rebase manually by commenting `@dependabot rebase`. [//]: # (dependabot-automerge-start) [//]: # (dependabot-automerge-end) --- <details> <summary>Dependabot commands and options</summary> <br /> You can trigger Dependabot actions by commenting on this PR: - `@dependabot rebase` will rebase this PR - `@dependabot recreate` will recreate this PR, overwriting any edits that have been made to it - `@dependabot merge` will merge this PR after your CI passes on it - `@dependabot squash and merge` will squash and merge this PR after your CI passes on it - `@dependabot cancel merge` will cancel a previously requested merge and block automerging - `@dependabot reopen` will reopen this PR if it is closed - `@dependabot close` will close this PR and stop Dependabot recreating it. You can achieve the same result by closing it manually - `@dependabot ignore this major version` will close this PR and stop Dependabot creating any more for this major version (unless you reopen the PR or upgrade to it yourself) - `@dependabot ignore this minor version` will close this PR and stop Dependabot creating any more for this minor version (unless you reopen the PR or upgrade to it yourself) - `@dependabot ignore this dependency` will close this PR and stop Dependabot creating any more for this dependency (unless you reopen the PR or upgrade to it yourself) - `@dependabot use these labels` will set the current labels as the default for future PRs for this repo and language - `@dependabot use these reviewers` will set the current reviewers as the default for future PRs for this repo and language - `@dependabot use these assignees` will set the current assignees as the default for future PRs for this repo and language - `@dependabot use this milestone` will set the current milestone as the default for future PRs for this repo and language - `@dependabot badge me` will comment on this PR with code to add a "Dependabot enabled" badge to your readme Additionally, you can set the following in your Dependabot [dashboard](https://app.dependabot.com): - Update frequency (including time of day and day of week) - Pull request limits (per update run and/or open at any time) - Out-of-range updates (receive only lockfile updates, if desired) - Security updates (receive only security updates, if desired) </details>