Dynamic versioning for feathr

Right now feathr version is hardcoded. There are plugins such as https://github.com/sbt/sbt-dynver or https://github.com/sbt/sbt-git that will let us automatically update the version.

Things to be aware of are any configurations that depend on our hardcoded versions, such as the feathr_config.yaml file, which references the 0.1.0 jar.

Potential options, is to auto generate this feathr_config.yaml as part of the assembly, such that it always references the latest version, or be able to have a dynamic version reference in the config.

Dynamic versioning would be beneficial for publishing to maven, as maven requires unique versions for releases