Fix checkversion with dev-like PYQT_VERSION_STR

The latest arch linux update included for PyQt6 included a version
string of the form '6.7.0.dev2404081550'. This crashed checkversion as
it expects plain integers. We now limit the integer conversion to the
first three parts of the split, which hopefully are always numbers.

vimiv/checkversion.py

@@ -37,7 +37,7 @@ def check_pyqt_version():
             "Please install / configure a valid wrapper to run vimiv.\n"
         )
 
-    pyqt_version = tuple(map(int, PYQT_VERSION_STR.split(".")))
+    pyqt_version = tuple(map(int, PYQT_VERSION_STR.split(".")[:3]))
     if pyqt_version < PYQT_REQUIRED_VERSION:
         _exit_version("PyQt", PYQT_REQUIRED_VERSION, pyqt_version)