build: move angular version to package.json (#794)

Author: CaerusKaru

build-config.js

@@ -4,16 +4,16 @@
  */
 const {join} = require('path');
 
-const package = require('./package.json');
+const packageJson = require('./package.json');
 
 /** Current version of the project*/
-const buildVersion = package.version;
+const buildVersion = packageJson.version;
 
 /**
  * Required Angular version for all Angular Layout packages. This version will be used
  * as the peer dependency version for Angular in all release packages.
  */
-const angularVersion = '^6.0.0';
+const angularVersion = packageJson.requiredAngularVersion;
 
 /** License that will be placed inside of all created bundles. */
 const buildLicense = `/**

package.json

@@ -8,6 +8,10 @@
     "type": "git",
     "url": "git+https://github.com/angular/flex-layout.git"
   },
+  "license": "MIT",
+  "engines": {
+    "node": ">= 5.4.1"
+  },
   "scripts": {
     "demo:serve": "gulp serve:devapp",
     "demo:stage": "gulp stage-deploy:devapp",
@@ -22,10 +26,7 @@
     "universal:serve": "gulp universal:serve"
   },
   "version": "6.0.0-beta.16",
-  "license": "MIT",
-  "engines": {
-    "node": ">= 5.4.1"
-  },
+  "requiredAngularVersion": ">=6.0.0 <7.0.0",
   "dependencies": {
     "@angular/cdk": "6.0.0",
     "@angular/common": "^6.0.0",