Bump pyqt5 from 5.15.4 to 5.15.5

Bumps [pyqt5](https://www.riverbankcomputing.com/software/pyqt/) from 5.15.4 to 5.15.5.

---
updated-dependencies:
- dependency-name: pyqt5
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

requirements.txt

@@ -1,5 +1,5 @@
 mypy==0.812
-PyQt5==5.15.4
+PyQt5==5.15.5
 PyQt5-stubs==5.15.2.0
 pytest==6.2.4
 coverage==6.0.2