- Deduplicate files in _jupyter_kernel_dir.

- Revert and clarify some specfile changes:
* fix kernelspec install for primary flavor
* BuildRequires debugpy is sufficiently declared once

- specfile:
* require debugpy for build
- update to version 6.4.1:
* Merged PRs
+ debugpy is now a build requirement #773 (@minrk)
- changes from version 6.4.0:
* Enhancements made
+ Make json_clean a no-op for jupyter-client >= 7 #708
(@martinRenou)
* Bugs fixed
+ Do not assume kernels have loops #766 (@Carreau)
+ Fix undefined variable #765 (@martinRenou)
* Maintenance and upkeep improvements
+ Make ipykernel work without debugpy #767 (@frenzymadness)
+ Stop using deprecated recv_multipart when using in-process
socket. #762 (@Carreau)
+ Update some warnings with instructions and version number. #761
(@Carreau)