Add API_KEY to CI environment

[Ryan Zimmerman]

Need to have an API key on the CI server in order to run some tests there. Relevant code:

cryptocompare/test/cryptocompare.test.js

Lines 7 to 14 in 6b2cc44

 const API_KEY = process.env.API_KEY 
  
 if (API_KEY) { 
   test('setup', t => { 
     cc.setApiKey(process.env.API_KEY) 
     t.end() 
   }) 
 } 

cryptocompare/test/cryptocompare.test.js

Line 278 in 6b2cc44

 if (API_KEY) {