Add support to external folder

What's Changed

• Fix action by @DantasB in #4
• Generate the action diagram to use on readme by @DantasB in #5
• Add answer location as github secret by @DantasB in #6
• Add validation on answers folder by @DantasB in #7

Full Changelog: v0.0.1-alpha...v0.1.0-alpha

Create the assignment corrector action

What's Changed

• Add the dockerfile with the main languages by @DantasB in #1
• Create the mocked action by @DantasB in #2
• Create the mocked entrypoint by @DantasB in #3

Full Changelog: https://github.com/DantasB/assignment-corrector/commits/v0.0.1-alpha