ci: Skip PyQt6 6.5.1 wheels

They are linked to a symbol from glibc 2.35, while claiming to be for
2.28, and Ubuntu 20.04 only has 2.31.

Author: QuLogic

.github/workflows/tests.yml

@@ -62,15 +62,21 @@ jobs:
             python-version: 3.9
             extra-requirements: '-r requirements/testing/extra.txt'
             CFLAGS: "-fno-lto"  # Ensure that disabling LTO works.
+            # https://github.com/matplotlib/matplotlib/pull/26052#issuecomment-1574595954
+            pyqt6-ver: '!=6.5.1'
             # https://bugreports.qt.io/projects/PYSIDE/issues/PYSIDE-2346
             pyside6-ver: '!=6.5.1'
           - os: ubuntu-20.04
             python-version: '3.10'
             extra-requirements: '-r requirements/testing/extra.txt'
+            # https://github.com/matplotlib/matplotlib/pull/26052#issuecomment-1574595954
+            pyqt6-ver: '!=6.5.1'
             # https://bugreports.qt.io/projects/PYSIDE/issues/PYSIDE-2346
             pyside6-ver: '!=6.5.1'
           - os: ubuntu-20.04
             python-version: '3.11'
+            # https://github.com/matplotlib/matplotlib/pull/26052#issuecomment-1574595954
+            pyqt6-ver: '!=6.5.1'
             # https://bugreports.qt.io/projects/PYSIDE/issues/PYSIDE-2346
             pyside6-ver: '!=6.5.1'
           - os: macos-latest