Update build status label to show Github Actions

[briwagner]

This replaces Travis-CI badge which is no longer in use.

Signed-off-by: Brian Wagner briwagner@outlook.com

Description

Motivation and Context

• issue 1671
• I have raised an issue to propose this change (required)
• My issue has received approval from the maintainers or lead with the design/approved label

How Has This Been Tested?

Markdown preview in VS Code shows passing status (currently accurate for build workflow status).

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• [ x] I've read the CONTRIBUTION guide
• [ x] I have signed-off my commits with git commit -s
• I have added tests to cover my changes.
• All new and existing tests passed.

[alexellis]

LGTM

[alexellis]

Thank you @briwagner 👍