fix typo in examples README: plural form examples

examples/README.md

@@ -1,6 +1,6 @@
 # Examples
 
-This folder contains numerous example showing how to use axum. Each example is
+This folder contains numerous examples showing how to use axum. Each example is
 setup as its own crate so its dependencies are clear.
 
 For a list of what the community built with axum, please see the list