Clarify required edits to projenrc.json

[tped]

Consider updating README to clarify required edits to .projenrc.json. It would be helpful to callout the significance of setting skillClass (required edit that must match init.py class name) and repositoryURL (required edit that needs to match the github repository for this skill).

Perhaps a couple of mods (bolded)to README:

After the skill has been created with default options, a file called .projenrc.json will be generated. This file contains all of the options used to create the skill, and will need to be edited to set the skill's initial configuration. For a full list of supported options, see API.md.

You will need to change the name, author, authorAddress, authorHandle, skillClass, and repositoryUrl options. skillClass must match the Class name in init.py and repositoryURL must match the Git repository set up for this this skill. If you prefer to have an explicitly named directory for your source code instead of the default src, then packageDir should also be set. The type option should be left alone, as it is used to tell projen which project template to use.

// Ultimately it would be nice if projen would automatically set the Class Name in init.py similar to how it currently updates URL in setup.py //