MapLibre Native support for index-of

[louwers]

After maplibre/maplibre-native#1113 is merged & released MapLibre Native (Android) will have support for index-of.

https://maplibre.org/maplibre-style-spec/expressions/#index-of

Creating an issue now so I don't forget later.

[wipfli]

@louwers please make sure to track in which version of the android SDK this feature is implemented in

maplibre-style-spec/src/reference/v8.json

Lines 2764 to 2772 in d2ce655

	"index-of": {
	"doc": "Returns the first position at which an item can be found in an array or a substring can be found in a string, or `-1` if the input cannot be found. Accepts an optional index from where to begin the search.",
	"group": "Lookup",
	"sdk-support": {
	"basic functionality": {
	"js": "1.10.0"
	}
	}
	},

which is used to generate the table at https://maplibre.org/maplibre-style-spec/expressions/#index-of