Update pylint requirement from ~=2.14 to ~=2.15

Updates the requirements on [pylint](https://github.com/PyCQA/pylint) to permit the latest version.
- [Release notes](https://github.com/PyCQA/pylint/releases)
- [Commits](pylint-dev/pylint@v2.14.0...v2.15.0)

---
updated-dependencies:
- dependency-name: pylint
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

requirements-test.txt

@@ -3,7 +3,7 @@ asynctest~=0.13
 flake8~=4.0
 flake8-docstrings~=1.6
 mypy==0.971
-pylint~=2.14
+pylint~=2.15
 pylint-strict-informational==0.1
 pytest~=7.1
 pytest-cov~=3.0