The MIT licence violates the copy left requirement of joomla/string #412

joomla/string is licensed under the GPL and is a requirement through wamania/php-stemmer.

Because GPL has a copy left requirement, both wamania/php-stemmer and rubix/ml are violating violating that requirement by being released under the MIT licence.

Unfortunately, it doesn't look like there is a simple drop in replacement for wamania/php-stemmer (maybe https://packagist.org/packages/nadar/stemming but it supports far fewer languages) and at the moment there is silence about moving away from joomla/string (wamania/php-stemmer#38).

As a simple fix for now, could wamania/php-stemmer maybe become a recommends instead of a dependency so that those of us not using the WordStemmer Tokenizer can at least avoid the complications?

I have submitted a PR to wamania/php-stemmer to move away from joomla\string, so if that is merged, we could bump the version here and the issue would go away.