Remove autocomplete prop

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Currently, we have an autocomplete prop to decide whether to add suggestions irrespective of whether they are selected.
It was added in #39 and has the below behaviour

- `true` - when the delimiter key (such as enter) is pressed, the first matching suggestion is used.
- `1` - when the delimiter key (such as enter) is pressed, the matching suggestion is used only if there is a single matching suggestion
- `false` (default) - tags are not autocompleted on enter/delimiter

As you can see it allows adding tags without selecting them when set to true and when setting the value to 1 it will allow adding only when there is one matching suggestion.

These behaviours are very specific to the host app and not intuitive as well. We should allow adding tags only when explicitly selected and hence will be removing this prop in 7.x

To ease the above process, we can introduce a new prop may be which decides whether to auto select the first matching suggestion when typing.

Thoughts welcome :) 🙏🏻

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cc @rnicholus, would like to know your thoughts too