Composer 2.0 deprecation warning

[samwilson]

With version 1.0.1 I'm getting the following deprecation notice:

Deprecation Notice: Class MikeVanRiel\TextToLatexTest located in ./vendor/mikevanriel/text-to-latex/tests/unit/src/MikeVanRiel/TextToLatexTest.php does not comply with psr-0 autoloading standard. It will not autoload anymore in Composer v2.0. in phar:///[...]/composer/src/Composer/Autoload/ClassMapGenerator.php:201

[mvriel]

Hey Sam, I wasn't aware that this package was actually used that much 😅 I don't have the time now, but I'll try and get that sorted. Should you beat me to it with a PR; that is of course much appreciated but not mandatory ;)

[samwilson]

I'm using it because it's in cebe/markdown-latex. :-)

I've made a PR; see what you think.