StepProgress

Fix some wording

StepProgress

• Introduced the stepAnimationDuration property in the constructor.

StepProgress

• Fixed bug preventing progression to the next step when on the final step.
• Added GitHub Actions for code analysis and running tests on push to the master branch.
• Wrote unit and widget tests.
• Updated documentation.
• Cleaned and refactored code.
• Renamed widget to StepProgress from Progress.
• Renamed repository to step_progress from step-progress.

initial package library

0.0.1

update README.md and add LICENSE