CuVec v6.0.1 stable

• improved str representations
• pybind11: local Shape
• fix tests
  • suppress cupy PerformanceWarning
  • pin Ubuntu 22.04 for Python 3.7 (#48)
  • fix segfault from SWIG 4.3 (swig/swig#3086)
• misc framework updates (#46, #39, tikitu/jsmin#44)
  • bump dependencies
  • minor linting