Upgrade sendgrid to 6.1.0

[fabaff]

Description:

Changelog: https://github.com/sendgrid/sendgrid-python/blob/master/CHANGELOG.md#610---2019-09-12

Example entry for configuration.yaml (if applicable):

notify:
  - name: sendgrid
    platform: sendgrid
    api_key: !secret sendgrid_api
    sender: !secret sendgrid_sender
    recipient: !secret sendgrid_recipient

Service call data:

{
  "message": "The sun is {% if is_state('sun.sun', 'above_horizon') %}up{% else %}down{% endif %}!"
}

Checklist:

• The code change is tested and works locally.
• Local tests pass with tox. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.
• I have followed the [development checklist][dev-checklist]

If the code communicates with devices, web services, or third-party tools:

• [The manifest file][manifest-docs] has all fields filled out correctly. Update and include derived files by running python3 -m script.hassfest.
• New or updated dependencies have been added to requirements_all.txt by running python3 -m script.gen_requirements_all.