Issue title: Unhandled 'error' event
 Issue body: Hello ,

I used the instruction of how to install the generator , but I faced this issue.

events.js:183
      throw er; // Unhandled 'error' event
      ^

TypeError: this.getJhipsterAppConfig is not a function
    at module.exports.readConfig 

I am using "jhipsterVersion": "5.8.0" , and angular 7.

thanks in advance
 Comments: 
 Comment 0: I think its because of latest changes from JHipster side. It is fixed with this PR https://github.com/sudheerj/generator-jhipster-primeng/pull/74
 Comment 1: Thanks, I will update now
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