The "green" status of this badge was actually last updated 4 years ago,
until I manually ran a master branch test today that made the current
Travis test failures in the React tests visible. But those test failures
seem to be Travis-related and not real (the same tests pass on
CircleCI). Maybe we can completely remove Travis by now, but let's
remove the now-failing badge for now to not scare users.

Signed-off-by: Julius Volz <julius.volz@gmail.com>