- Update requirements and test suite setup

- specfile:
* update requirements
* switch to pyproject.toml build
- update to version 6.15.0:
* Bugs fixed
+ Fix compatibility with tornado 6.2 beta #956 (@minrk)
* Maintenance and upkeep improvements
+ Back to top-level tornado IOLoop #958 (@minrk)
+ Explicitly require pyzmq >= 17 #957 (@minrk)
+ [pre-commit.ci] pre-commit autoupdate #954 (@pre-commit-ci)
- changes from version 6.14.0:
* Enhancements made
+ Add cpu_count to the usage_reply #952 (@echarles)
* Bugs fixed
+ use pss memory info type if available for the resource usage
reply #948 (@echarles)
+ Ensure psutil for the process is accurate #937 (@echarles)
* Maintenance and upkeep improvements
+ Fix sphinx 5.0 support #951 (@blink1073)
+ [pre-commit.ci] pre-commit autoupdate #950 (@pre-commit-ci)
- changes from version 6.13.1:
* Bugs fixed
+ Fix richInspectVariables #943 (@davidbrochart)
+ Force debugger metadata in built wheel #941 (@blink1073)
* Maintenance and upkeep improvements
+ [pre-commit.ci] pre-commit autoupdate #945 (@pre-commit-ci)
+ Clean up typings #939 (@blink1073)
+ [pre-commit.ci] pre-commit autoupdate #938 (@pre-commit-ci) (forwarded request 984608 from bnavigator)