Update GR_jll to Qt6.5

[barche]

The Qt6 JLL in Yggdrasil was updated to version 6.5, so it would be nice to set that as new required version. For this, the dependency should be specified as follows when building the next GR_jll:

Dependency("Qt6Base_jll"; compat="~6.5.2"),

[jheinen]

I tried this (see 7371) but it fails due to GLIBCXX linker problems:

[08:05:26] /opt/x86_64-linux-gnu/bin/../lib/gcc/x86_64-linux-gnu/9.1.0/../../../../x86_64-linux-gnu/bin/ld: /workspace/destdir/lib/libQt6Widgets.so.6.5.2: undefined reference to `std::pmr::monotonic_buffer_resource::~monotonic_buffer_resource()@GLIBCXX_3.4.28'
--
  | [08:05:26] /opt/x86_64-linux-gnu/bin/../lib/gcc/x86_64-linux-gnu/9.1.0/../../../../x86_64-linux-gnu/bin/ld: /workspace/destdir/lib/libQt6Widgets.so.6.5.2: undefined reference to `vtable for std::pmr::monotonic_buffer_resource@GLIBCXX_3.4.28'
  | [08:05:26] collect2: error: ld returned 1 exit status
  | [08:05:26] make[2]: *** [CMakeFiles/gksqt.dir/build.make:178: gksqt] Error 1

[barche]

Yes, I forgot to mention that Qt 6.5 needs GCC 10, should be fixed now. Anyway, thanks for the quick reaction, since this issue was just intended as a heads-up to remember to move to Qt 6.5 it can be closed.