chore(release): Release v2.1.1
chore(README): Fix header styling
docs(tagsInput): Fix type option documentation [skip ci]
docs(README): Fix link to the API documentation page
chore(package.json): Add main property
chore(release): Bump version to 2.2.0
fix(tags-input.html): option to enable/disable spellcheck

As before spellcheck is enabled by default unless explicitly disabled.
This matches native browser functionality.
The attribute name `spellcheck` is the same as the html attribute for
`input` tags, so the api should be familiar to users.