Update a specific dashboard.

def _update(dashboard, profile):
    '''Update a specific dashboard.'''
    payload = {
        'dashboard': dashboard,
        'overwrite': True
    }
    request_url = "{0}/api/dashboards/db".format(profile.get('grafana_url'))
    response = requests.post(
        request_url,
        headers={
            "Authorization": "Bearer {0}".format(profile.get('grafana_token'))
        },
        json=payload
    )
    return response.json()