0.26.0

• When title is not set in configuration settings, use mqttwarn: {topic}
  instead of mqttwarn only. Thanks, Rob!
• Add launch configuration for VSCode. Thanks, David!
• Use STDERR as default log target
• Stop including the "tests" folder into the sdist package
• Add "mqttwarn-contrib" package to the list of "extra" dependencies
• Improve launching service plugins interactively from the command line
  Now, there are two options "--config" and "--options" to be able to
  obtain all relevant bits of information from the command line.