Add license scan report and status

[fossabot]

Your FOSSA integration was successful! Attached in this PR is a badge and license report to track scan status in your README.

Below are docs for integrating FOSSA license checks into your CI:

• CircleCI
• TravisCI
• Jenkins
• Other

[fossabot]

Your license scan is passing -- congrats!

Your badge status is now updated and ready to merge:

[otiai10]

@fossabot rebase