update build script

Author: zebzhao

gulpfile.js

@@ -37,7 +37,6 @@
     "lint": "ng lint",
     "e2e": "ng e2e",
     "ngcompile": "npm run build",
-    "build:esm": "gulp inline-templates && npm run ngcompile",
     "build:esm:watch": "npm build:watch",
     "build:umd": "npm run build",
     "build:umd:watch": "npm build:watch",
@@ -47,7 +46,8 @@
     "codecov": "cat coverage/lcov.info | codecov",
     "docs": "compodoc -p tsconfig.json -d docs --disableCoverage",
     "explorer": "source-map-explorer ./dist/angular2-query-builder/bundles/angular2-query-builder.umd.js",
-    "gh-pages": "rimraf docs && npm run docs && gulp copy:demo && gh-pages -d docs",
+    "copyDemo": "copyfiles -u 2 demo/dist/**/* docs",
+    "gh-pages": "rimraf docs && npm run docs && npm run copyDemo && gh-pages -d docs",
     "postversion": "git push && git push --tags",
     "prebuild": "rimraf dist tmp",
     "prebuild:watch": "rimraf dist tmp",
@@ -79,8 +79,6 @@
     "compodoc": "^0.0.41",
     "core-js": "^2.6.5",
     "gh-pages": "^2.2.0",
-    "gulp": "4",
-    "gulp-inline-ng2-template": "^5.0.1",
     "jasmine-core": "^3.4.0",
     "jasmine-spec-reporter": "^4.2.1",
     "karma": "^4.1.0",
@@ -98,5 +96,8 @@
     "tslint": "^5.15.0",
     "typescript": "3.4.5",
     "zone.js": "^0.9.1"
+  },
+  "dependencies": {
+    "copyfiles": "^2.2.0"
   }
 }