Bump pyqtwebengine-qt5 from 5.15.15 to 5.15.16

Bumps [pyqtwebengine-qt5](https://www.riverbankcomputing.com/software/pyqt/) from 5.15.15 to 5.15.16.

---
updated-dependencies:
- dependency-name: pyqtwebengine-qt5
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

REQUIREMENTS.txt

@@ -109,7 +109,7 @@ PyQt5==5.15.11
 PyQt5-Qt5==5.15.16
 PyQt5-sip==12.16.1
 PyQtWebEngine==5.15.7
-PyQtWebEngine-Qt5==5.15.15
+PyQtWebEngine-Qt5==5.15.16
 pyrsistent==0.20.0
 python-dateutil==2.9.0.post0
 python-lsp-black==2.0.0