Separate documentation dependencies (#874)

* separate documentation dependencies

* bump deps

* update netlify config and package scripts

* bump netlify

* add cross-env

* fix publish path

docs/package.json

@@ -0,0 +1,26 @@
+{
+  "name": "@vue-select/docs",
+  "version": "1.0",
+  "license": "MIT",
+  "scripts": {
+    "serve": "vuepress dev",
+    "build": "vuepress build",
+    "build:preview": "cross-env DEPLOY_PREVIEW=true vuepress build"
+  },
+  "devDependencies": {
+    "@vuepress/plugin-active-header-links": "^1.0.0-alpha.47",
+    "@vuepress/plugin-google-analytics": "^1.0.0-alpha.47",
+    "@vuepress/plugin-nprogress": "^1.0.0-alpha.47",
+    "@vuepress/plugin-pwa": "^1.0.0-alpha.47",
+    "@vuepress/plugin-register-components": "^1.0.0-alpha.47",
+    "@vuepress/plugin-search": "^1.0.0-alpha.47",
+    "cross-env": "^5.2.0",
+    "fuse.js": "^3.4.4",
+    "gh-pages": "^0.11.0",
+    "node-sass": "^4.12.0",
+    "sass-loader": "^7.1.0",
+    "vue": "^2.6.10",
+    "vuepress": "^1.0.0-alpha.47",
+    "vuex": "^3.1.0"
+  }
+}