title: <ngx-qrcode> isn't known element in ionic 4
body: <p>Since working for a QR code scanning application in ionic 4, I continuously get the error called as below:</p>
  
  <p>Error: Template parse errors:
  Can't bind to 'qrc-value' since it isn't a known property of 'ngx-qrcode'.
  1. If 'ngx-qrcode' is an Angular component and it has 'qrc-value' input, then verify that it is part of this module.
  2. If 'ngx-qrcode' is a Web Component then add 'CUSTOM_ELEMENTS_SCHEMA' to the '@NgModule.schemas' of this component to suppress this message.
  3. To allow any property add 'NO_ERRORS_SCHEMA' to the '@NgModule.schemas' of this component. ("</p>
  
  <pre><code>&lt;ion-card *ngIf="createdCode"&gt;
  &lt;ngx-qrcode [ERROR -&gt;][qrc-value]="createdCode"&gt;&lt;/ngx-qrcode&gt;
  &lt;ion-card-content&gt;
  </code></pre>
  
  <p>Please help me solve this.</p>