Add info about the new Psalm support model

Author: danog

README.md

@@ -19,6 +19,14 @@ You can play around with Psalm [on its website](https://psalm.dev/).
 
 Documentation is available on [Psalm’s website](https://psalm.dev/docs), generated from the [docs](https://github.com/vimeo/psalm/blob/master/docs) folder.
 
+## Support Psalm development
+
+You can support Psalm development by requesting a support contract from [Daniil Gentili](https://daniil.it), the only active maintainer of Psalm.  
+
+Support contracts can cover full integration of Psalm into existing codebases, support for Psalm issues and development of additional Psalm features.  
+
+See [here »](https://daniil.it) for info, pricing and contact information.  
+
 ## Interested in contributing?
 
 Have a look at [CONTRIBUTING.md](CONTRIBUTING.md).
@@ -27,6 +35,8 @@ Have a look at [CONTRIBUTING.md](CONTRIBUTING.md).
 
 Built by Matt Brown ([@muglug](https://github.com/muglug)).
 
-Maintained by Orklah ([@orklah](https://github.com/orklah)), Daniil Gentili ([@danog](https://github.com/danog)), and Bruce Weirdan ([@weirdan](https://github.com/weirdan)).
+Maintained by Daniil Gentili ([@danog](https://github.com/danog)).
+
+Former maintainers: Orklah ([@orklah](https://github.com/orklah)) and Bruce Weirdan ([@weirdan](https://github.com/weirdan)).
 
 The engineering team at [Vimeo](https://github.com/vimeo) have provided a lot encouragement, especially [@nbeliard](https://github.com/nbeliard), [@erunion](https://github.com/erunion) and [@nickyr](https://github.com/nickyr).