uefi: Update MSRV policy language

Since there are now more releases since 1.68, drop the "in the future" bit.

Author: nicholasbishop

uefi/README.md

@@ -52,7 +52,7 @@ For additional information, refer to the [UEFI specification][spec].
 The minimum supported Rust version is currently 1.68, which is the first Rust
 release that fully supports all necessary features on the stable channel.
 
-In the future, our policy will be to support at least the past two stable releases.
+Our policy is to support at least the past two stable releases.
 
 ## License