Release 1.1.0 is using PHP 7.4 features but composer references PHP>=7.3

I would submit a PR, but wasn't entirely sure which approach you'd prefer;

• remove 1.1.0 & do a 2.0.0 for PHP7.4, or
• strip the types from props for 1.1.1

<3

Originally posted by @cmacdonald-au in #4 (comment)