Update sbt-ghpages to 0.7.0

[scala-steward]

Updates com.typesafe.sbt:sbt-ghpages from 0.6.3 to 0.7.0.

I'll automatically update this PR to resolve conflicts as long as you don't change it yourself.

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Adjust future updates

Add this to your `.scala-steward.conf` file to ignore future updates of this dependency: ``` updates.ignore = [ { groupId = "com.typesafe.sbt", artifactId = "sbt-ghpages" } ] ``` Or, add this to slow down future updates of this dependency: ``` dependencyOverrides = [{ pullRequests = { frequency = "@monthly" }, dependency = { groupId = "com.typesafe.sbt", artifactId = "sbt-ghpages" } }] ```

labels: sbt-plugin-update, early-semver-major, semver-spec-minor, commit-count:1