Convenience update scripts | Up pub.dev score

[timrijckaert]

Prepare for pub.dev upload

Add script that will prepare for pub release.
Pub requires:

• Provide a file named README.md.
• Provide a file named CHANGELOG.md.
• Maintain an example.

As the sealed_class_generator consist of two mutually exclusive packages:

• the annotation inside the sealed_class folder
• the actual generator code inside the sealed_class_generator folder.

At the root level we have files that are relevant for both packages:

• README.md.
• CHANGELOG.md.
• LICENSE

We also have an example/ folder which combines the two packages.

Essentially the sealed_class_generator is one piece with 2 packages:

• one for runtime
• one for only compiling.

Essentially we want a script that prepares this package for easy upload to pub.dev
This script should do:

• Copy the root LICENSE to the sealed_class and the sealed_class_generator
• Copy the root README.md to the sealed_class and the sealed_class_generator
• Copy the root CHANGELOG.md to the sealed_class and the sealed_class_generator

Prepare for version upgrade

Every time we want to upgrade this package we need to do the following:

• Input the new version name
• Input a new change log
• Update the README version number
• Update the pubspec from the sealed_class folder
• Update the pubspec from the sealed_class_generator folder
• DartFMT everything 🕺
• Check output of pana and see if it does not contain any error's.