Fix forge-platform-support URL

Apparently it got changed.

RELEASES.md

@@ -912,7 +912,7 @@ Compatibility Notes
 [`Duration::mul_f32`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.mul_f32
 [`Duration::mul_f64`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.mul_f64
 [`any::type_name`]: https://doc.rust-lang.org/std/any/fn.type_name.html
-[forge-platform-support]: https://forge.rust-lang.org/platform-support.html
+[forge-platform-support]: https://forge.rust-lang.org/release/platform-support.html
 [pipeline-internals]: https://internals.rust-lang.org/t/evaluating-pipelined-rustc-compilation/10199
 
 Version 1.37.0 (2019-08-15)