uthash: update to 2.2.0.

Version 2.2.0 (2020-12-17)
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* add HASH_NO_STDINT for platforms without C99 <stdint.h>
* silence many -Wcast-qual warnings (thanks, Olaf Bergmann!)
* skip hash computation when finding in an empty hash (thanks, Huansong Fu!)
* rename oom to utarray_oom, in utarray.h (thanks, Hong Xu!)
* rename oom to utstring_oom, in utstring.h (thanks, Hong Xu!)
* remove MurmurHash/HASH_MUR

(fcambus)