chore(deps): update pyqt5 requirement from >=5.15 to >=5.15.11

Updates the requirements on [pyqt5](https://www.riverbankcomputing.com/software/pyqt/) to permit the latest version.

---
updated-dependencies:
- dependency-name: pyqt5
  dependency-version: 5.15.11
  dependency-type: direct:production
...

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

Author: dependabot[bot]

requirements.txt

@@ -1,3 +1,3 @@
-PyQt5 >= 5.15
+PyQt5 >= 5.15.11
 pywin32 >= 300  
 psutil >= 5.8