Paradox 0.6.9

Changes

• Dependency directive: symbolic version numbers #413 by @ennru
• Use 'dotted' convention for maven properties [#414] by @raboof
• Simplify release procedure #396 by @raboof

Updates

• Update ST4 to 4.3 #407 by @scala-steward
• Update sbt-ci-release to 1.5.2 #409 by @scala-steward
• Update jsoup to 1.12.2 #410 by @scala-steward
• Update sbt, scripted-plugin to 1.3.8 #408 by @scala-steward
• Update sbt-header to 5.4.0 #402 by @scala-steward
• Update sbt-paradox to 0.6.8 #398 by @scala-steward
• Make paradox/default-theme succeed regardless of current year #403 by @raboof