Dependabot version updates no longer support Elm 0.18. This version of Elm was hosted on Bintray, which was shut down on May 1, 2021. Dependabot still supports Elm 0.19, so please migrate if you wish to continue using Dependabot.
You can now use the web UI to synchronize an out of date branch of a fork with its upstream branch. If there are no merge conflicts between the branches, the fork's branch is updated either by fast-forwarding or by merging from the upstream's branch. If there are conflicts, you will be prompted to open a pull request to resolve.