refactor(CI): don't pass the quiet option to pnpm

pnpm is quiet on CI servers by default from v0.26.2

.travis.yml

@@ -6,7 +6,7 @@ sudo: false
 before_install:
   - npm install -g pnpm
 install:
-  - pnpm install --quiet
+  - pnpm install
 script:
   - npm test
   - if [[ $TRAVIS_NODE_VERSION == "4" ]]; then npm run docs:build; fi

appveyor.yml

@@ -6,7 +6,7 @@ install:
   - ps: Install-Product node $env:nodejs_version
   - npm set fetch-retry-maxtimeout 180000
   - npm install -g pnpm
-  - pnpm install --quiet
+  - pnpm install
 matrix:
   fast_finish: true
 build: off