Figure out how to keep gradle dependencies fresh after 1.0 release.

[zach-klippenstein]

We used to use Dependabot to ensure we kept our dependencies on their latest versions, but it does not support our Dependencies.kt file. There are a number of options here, which need to be evaluated and actually tested to see what works. One is the refreshVersions gradle plugin, which Zach tried and ran into issues with. There are a bunch of other similar plugins linked here. This is a Gradle Action for detecting out-of-date versions, but doesn't automatically update anything.

cc @rjrjr