title: Treating warnings as errors because process.env.CI = true. Failed to compile
body: <p>I am working on a react-weather application for self learning purpose.
  Deployed the same in gh-pages. <br/>
  URL <br/>
  <strong><a href="https://davisraimon.github.io/react-weather/" rel="noreferrer">https://davisraimon.github.io/react-weather/</a></strong> <br/>
  Repo <br/>
  <strong><a href="https://github.com/davisraimon/react-weather" rel="noreferrer">https://github.com/davisraimon/react-weather</a></strong> <br/><br/>
  When tried to integrate my application with <strong>Travis Ci</strong>, i got error as follows.
  It says like i have to change some env variable called Process.env.CI.</p>
  <pre><code>$ git clone --depth=50 --branch=master https://github.com/davisraimon/react-weather.git davisraimon/react-weather
  nvm.install
  4.18s$ nvm install stable
  cache.1
  Setting up build cache
  cache.npm
  $ node --version
  v14.4.0
  $ npm --version
  6.14.5
  $ nvm --version
  0.35.3
  install.npm
  13.21s$ npm ci 
  7.45s$ npm run build
  &gt; react-weather@0.1.0 build /home/travis/build/davisraimon/react-weather
  &gt; react-scripts build
  Creating an optimized production build...
  Treating warnings as errors because process.env.CI = true.
  Most CI servers set it automatically.
  Failed to compile.
  ./src/components/form.component.js
    Line 1:17:  'Component' is defined but never used  no-unused-vars
  ./src/App.js
    Line 2:8:    'logo' is defined but never used              no-unused-vars
    Line 8:7:    'API_key' is assigned a value but never used  no-unused-vars
    Line 37:5:   Expected a default case                       default-case
    Line 53:14:  Expected '===' and instead saw '=='           eqeqeq
    Line 69:20:  Expected '===' and instead saw '=='           eqeqeq
  npm ERR! code ELIFECYCLE
  npm ERR! errno 1
  npm ERR! react-weather@0.1.0 build: `react-scripts build`
  npm ERR! Exit status 1
  npm ERR! 
  npm ERR! Failed at the react-weather@0.1.0 build script.
  npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
  npm ERR! A complete log of this run can be found in:
  npm ERR!     /home/travis/.npm/_logs/2020-06-30T17_45_07_887Z-debug.log
  The command &quot;npm run build&quot; exited with 1.
  cache.2
  store build cache
  </code></pre>
  <p>I added env variable in .travis.yml file.</p>
  <pre><code>env:
      process.env.CI : false
  </code></pre>
  <p>Still its showing the same error.</p>
  <p>Can anyone help me out of this situation please...</p>