xsum pip update

This release contains,

• workflow update, including action to upload xsum to PyPi
• workflow publish update from macOS to Ubuntu
• fix missing files for build and publish and fix the correct PATH

xsum pip update

This release contains,

• update the pip installation to avoid issues reported #1
• remove Travis from the CI
• update the GitHub actions, Appveyor, and versioneer

XSUM production release (update)

XSUM production release

• Update README file
• Update the MANIFEST file for conda installation

XSUM production release

1.1.0

Update to macos-latest to publish to PyPi

XSUM initial release.

The initial release of the XSUM library