Add rules for license copyright notice (fixes #44)

[mProjectsCode]

Added a plain text parser to parse plain text files, like LICENSE. Then, added two validations as part of the validate-license rule.

1. The copyright notice may not mention Dynalist Inc.
2. The copyright year must be up to date.

The PR includes tests as well.

Fixes #44

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[saberzero1]

Hey,

Looks great. I have a small remark: wouldn't the check flag all plugins once the year rolls over?

[mProjectsCode]

Yep, that was the plan.

For an automated scan config for existing plugins, one would probably want to disable that sub-rule.

[saberzero1]

Yep, that was the plan.

For an automated scan config for existing plugins, one would probably want to disable that sub-rule.

Check. That makes sense.

[claremacrae]

I had a similar thought, but for all the plugin PRs that were submitted one year, and are still in the queue in open PRs on 1st January….

[saberzero1]

I had a similar thought, but for all the plugin PRs that were submitted one year, and are still in the queue in open PRs on 1st January….

Perhaps adding something like an environment variable to override the year? That way, the CI checks can pass the year of the date that the PR was opened.

[mProjectsCode]

Added two rule options, one to set the year to validate against, and one to disable the year validation entirely.