TST: Skip PySide6 6.5.1 for testing

This version is buggy with respect to signals, and causes tests to fail:
- https://bugreports.qt.io/projects/PYSIDE/issues/PYSIDE-2346
- https://bugreports.qt.io/projects/PYSIDE/issues/PYSIDE-2348

Author: QuLogic

.github/workflows/tests.yml

@@ -62,13 +62,21 @@ jobs:
             python-version: 3.9
             extra-requirements: '-r requirements/testing/extra.txt'
             CFLAGS: "-fno-lto"  # Ensure that disabling LTO works.
+            # 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://bugreports.qt.io/projects/PYSIDE/issues/PYSIDE-2346
+            pyside6-ver: '!=6.5.1'
           - os: ubuntu-20.04
             python-version: '3.11'
+            # https://bugreports.qt.io/projects/PYSIDE/issues/PYSIDE-2346
+            pyside6-ver: '!=6.5.1'
           - os: macos-latest
             python-version: 3.9
+            # https://bugreports.qt.io/projects/PYSIDE/issues/PYSIDE-2346
+            pyside6-ver: '!=6.5.1'
 
     steps:
       - uses: actions/checkout@v3