build: use npm5 instead of yarn

Author: filipesilva

.appveyor.yml

@@ -7,15 +7,15 @@ matrix:
 
 install:
   - ps: Install-Product node $env:nodejs_version
-  - yarn --frozen-lockfile
+  - npm install -g npm@~5.3.0
+  - npm install
 
 test_script:
   - node --version
-  - yarn --version
+  - npm --version
   - node tests\run_e2e.js --appveyor
 
 build: off
 
 cache:
   - node_modules
-  - "%LOCALAPPDATA%/Yarn"

.circleci/config.yml

@@ -8,7 +8,9 @@ jobs:
       - checkout
       - restore_cache:
           key: angular-cli-{{ .Branch }}-{{ checksum "yarn.lock" }}
-      - run: yarn --frozen-lockfile
+      - run: |
+          npm install -g npm@~5.3.0
+          npm install
       - save_cache:
           key: angular-cli-{{ .Branch }}-{{ checksum "yarn.lock" }}
           paths:

.travis.yml

@@ -7,7 +7,6 @@ addons:
 language: node_js
 
 cache:
-  yarn: true
   directories:
      - ./node_modules
 
@@ -92,14 +91,11 @@ matrix:
 
 
 before_install:
-  # Install yarn.
-  - curl -o- -L https://yarnpkg.com/install.sh | bash
-  - export PATH="$HOME/.yarn/bin:$PATH"
-  - yarn config set spin false
-  - yarn config set progress false
+  # Install npm 5.
+  - npm install -g npm@~5.3.0
 
 install:
-  - yarn --frozen-lockfile
+  - npm install
 
 env:
   global: