Add Clover Health

[saraatclover]

Add a health.yml and include Clover Health's information there:

companies:
  - name: Clover Health
    url: http://www.cloverhealth.com
    twitter: Clover_Health
    img: clover-health.png
    diversitydata: Yes
    eeo-1: Yes
    documentation: https://technology.cloverhealth.com/clover-healths-first-diversity-data-report-942f82648993
    date-updated: 2017
    status: Yes

Our icon is attached.