* ci: update to checkout v6
v4 and older causes warnings about deprecated node.js
* ci: update to actions cache v5
the older versions cause deprecation warings for node.js 20
* add compile option 'SIMDJSON_ENABLE_NAN_INF' but disable by default
* extend parser to support NaN/Infinity when SIMDJSON_ENABLE_NAN_INF=1
* update tests to check parsing of NaN/Infinity, when enabled
* update minefield tests: mark nan/inf tests as passing when nan/inf is ON
* update CI/CD to run tests with extensions for NaN/Infinity enabled
Paul Dreik