Add FastSchema to Readme (#737)

Author: ngocphuongnb

README.md

@@ -168,6 +168,7 @@ func main() {
 * [Tork](https://www.tork.run/) integrates Expr into its workflow execution.
 * [Critical Moments](https://criticalmoments.io) uses Expr for it's mobile realtime conditional targeting system.
 * [WoodpeckerCI](https://woodpecker-ci.org) uses Expr for [filtering workflows/steps](https://woodpecker-ci.org/docs/usage/workflow-syntax#evaluate).
+* [FastSchema](https://github.com/fastschema/fastschema) - A BaaS leveraging Expr for its customizable and dynamic Access Control system.
 
 [Add your company too](https://github.com/expr-lang/expr/edit/master/README.md)