cysimdjson v21.11 beta 1

The beta release after cycle of the internal stabilisation.

What's Changed

• Introduce a parser from string. by @ateska in #16
• Add export-to-Python methods and dict-like .get() by @ateska in #18
• Upgrade to SIMDJSON v0.9.6 by @ateska in #19
• Add a C API by @ateska in #20
• Significant refactoring that changes the approach to the "element". by @ateska in #21

Full Changelog: 21.4-alpha...21.11-beta