ci(npm): cache node modules in each CI config

.travis.yml

@@ -3,6 +3,10 @@ language: node_js
 node_js:
   - 8
   - 9
+# keep the npm cache to speed up installs
+cache:
+  directories:
+  - "$HOME/.npm"
 after_success:
   - npx nyc report --reporter=lcov | npx codecov
   - npm run cov:check

appveyor.yml

@@ -5,6 +5,9 @@ environment:
 
 version: "{build}"
 
+cache:
+  - node_modules -> package.json
+
 install:
   - ps: Install-Product node $env:nodejs_version
   - node --version

src/cli/tests/cli.integration.spec.ts

@@ -489,12 +489,12 @@ test(`${TestDirectories.six}: Sandboxed: yarn, no initial commit`, async t => {
     'test-6/.gitignore': 'a5d12062173e075833f8ca6f754d6d43',
     'test-6/.npmignore': 'd32d96087924f360f31b0438bb69d17e',
     'test-6/.prettierignore': '1da1ce4fdb868f0939608fafd38f9683',
-    'test-6/.travis.yml': '8ba04203d5a1c6e0304fef52123a45fc',
+    'test-6/.travis.yml': '37c491db59862df6ae963ee1250ed1bf',
     'test-6/.vscode/launch.json': '17407a15e4276d088a9bbe9ae886fa65',
     'test-6/.vscode/settings.json': '10c634c5fef6ecd298b6e41bf159f2cc',
     'test-6/LICENSE': '1f08fdd25d16c4ee8d5233b9cb7f6051',
     'test-6/README.md': 'd809bcbf240f44b51b575a3d49936232',
-    'test-6/appveyor.yml': 'c889f967e607510860d754a031fdf93c',
+    'test-6/appveyor.yml': 'ad473b824b29edfd21c18cfc8ae8e0ea',
     'test-6/package.json': 'a7a94f6c500a05c90e475049103ba26e',
     'test-6/src/index.ts': 'fbc67c2cbf3a7d37e4e02583bf06eec9',
     'test-6/src/lib/async.spec.ts': '1e83b84de3f3b068244885219acb42bd',