chart-releaser looks at the project history to determine whether a
chart changed, we mustn't limit the fetch depth.
Signed-off-by: Stephen Kitt <skitt@redhat.com>
Use the official Helm chart releasing GitHub Action instead of our
custom bash.
Travis CI can be removed after this commit, as all tests will have
equivalents for GHAs.
Closes: #71
Signed-off-by: Daniel Farrell <dfarrell@redhat.com>