Intent to abandon

[stof]

As I'm not using that library myself anymore (I have completed the migration to symfony/mailer years ago), I have no interest in continuing maintenance of the stampie packages.

Looking at the packagists stats, stempie-bundle has no installs at all over the last 30 days (and probably even longer than that according to the graph) while stampie/stampie and stampie/extra still have a few monthly installs but quite low.

I intent to officially mark this library (and the associated stampie/extra and stampie/stampie-bundle packages) as abandoned (suggesting symfony/mailer as replacement), unless someone else decides to step in as maintainer. At that point, the GitHub repositories will also be archived.