Newer versions of PHP raise a warning if you attempt to use array syntax
against non-strings / non-arrays. Added sanity check to ensure we're
working with a string, otherwise skip it.
Also added in PHP 8.1 to the testing suite and bumped the copyright.
Bumped version to 2.0 since as the change in expected output is a
breaking change.
* Updated to test again PHP 7.4 and to use that for coverage reporting.
* Added PHP nightly builds as an allowable failure.
* Added a git ignore as well as a `phpunit` configuration.
* Updated the tests and CI configuration to better handle the juggling of PHP and `phpunit` versions.
* Updated the coveralls dependency to be the latest and greatest instead of the deprecated package.
* Tweaked the README, updated the LICENSE years and bumped this package's version.
* Dropped Patreon link in favor of using Github Sponsors.
