ci(install): use package lock for install (#12154)

.travis.yml

@@ -13,7 +13,7 @@ branches:
 cache: npm
 
 install:
-  - npm install
+  - npm ci
   - |-
     if [ "$DIALECT" = "postgres-native" ]; then npm install pg-native; fi
 

CONTRIBUTING.md

@@ -36,11 +36,11 @@ Here comes a little surprise: You need [Node.JS](http://nodejs.org).
 
 ### 2. Install the dependencies
 
-Just "cd" into sequelize directory and run `npm install`, see an example below:
+Just "cd" into sequelize directory and run `npm ci`, see an example below:
 
 ```sh
 $ cd path/to/sequelize
-$ npm install
+$ npm ci
 ```
 
 ### 3. Database

appveyor.yml

@@ -14,12 +14,7 @@ environment:
 
 install:
   - ps: Install-Product node $env:NODE_VERSION x64
-  - ps: |
-      $pkg = ConvertFrom-Json (Get-Content -Raw package.json)
-      $pkg.devDependencies.PSObject.Properties.Remove('sqlite3')
-      $pkg.devDependencies.PSObject.Properties.Remove('pg-native')
-      ConvertTo-Json $pkg | Out-File package.json -Encoding UTF8
-  - npm install
+  - npm ci
 
 build: off