chore: fix broken links in CHANGELOG

Author: CaerusKaru

CHANGELOG.md

@@ -8,7 +8,7 @@ The 2.0.0-beta.10 and beta.11 releases on npm accidentally glitched-out midway,
 Similar to those used in **@angular/material**, this release also upgrades the package dependencies to Angular ~5.1.0 and the RxJS 5.5.x. 
 >  [Lettable RxJS operators](https://github.com/ReactiveX/rxjs/blob/master/doc/lettable-operators.md) are now used instead of prototype-patching *add* operators. 
 
-* **packages:** update deps to Angular v5 and RxJs 5.5 ([#523](https://github.com/angular/flex-layout/523)) ([62457a5972](https://github.com/angular/flex-layout/commit/62457a5972)), closes [#519](https://github.com/angular/flex-layout/issue/519)
+* **packages:** update deps to Angular v5 and RxJs 5.5 ([#523](https://github.com/angular/flex-layout/pull/523)) ([62457a5972](https://github.com/angular/flex-layout/commit/62457a5972)), closes [#519](https://github.com/angular/flex-layout/issues/519)
 
 
 <a name="2.0.0-beta.11"></a>