Relax typescript constraint

Author: mpalourdio

package.json

@@ -65,7 +65,7 @@
     "rxjs": "^6.0.0",
     "ts-node": "~5.0.1",
     "tslint": "~5.9.1",
-    "typescript": "2.7.2",
+    "typescript": "~2.7.2",
     "zone.js": "^0.8.26"
   },
   "engines": {

yarn.lock

@@ -7111,7 +7111,7 @@ typedarray@^0.0.6:
   version "0.0.6"
   resolved "https://registry.yarnpkg.com/typedarray/-/typedarray-0.0.6.tgz#867ac74e3864187b1d3d47d996a78ec5c8830777"
 
-typescript@2.7.2, "typescript@>=2.6.2 <2.8", typescript@~2.7.2:
+"typescript@>=2.6.2 <2.8", typescript@~2.7.2:
   version "2.7.2"
   resolved "https://registry.yarnpkg.com/typescript/-/typescript-2.7.2.tgz#2d615a1ef4aee4f574425cdff7026edf81919836"