fix(package.json): specify masonry-layout as a peer dependency

Author: edoparearyee

package.json

@@ -35,7 +35,8 @@
     "postrelease": "npm run packagr"
   },
   "peerDependencies": {
-    "@angular/core": ">=5.0.0 <6.0.0 || >=5.0.0-beta <6.0.0"
+    "@angular/core": ">=5.0.0 <6.0.0 || >=5.0.0-beta <6.0.0",
+    "masonry-layout": ">=4.0.0 <5.0.0"
   },
   "dependencies": {},
   "devDependencies": {