Bump mypy from 1.4.1 to 1.5.1 (#852)

Bumps [mypy](https://github.com/python/mypy) from 1.4.1 to 1.5.1.
- [Commits](python/mypy@v1.4.1...v1.5.1)

---
updated-dependencies:
- dependency-name: mypy
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

test-requirements.txt

@@ -2,7 +2,7 @@ pycodestyle==2.11.0
 pydocstyle==6.3.0
 dodgy==0.2.1
 isort==5.12.0
-mypy==1.4.1
+mypy==1.5.1
 Werkzeug==1.0.1
 Flask-Testing==0.8.1
 blinker==1.6.2