correction for LICENSE reference in README.md

Proposed changes

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Types of changes

What types of changes does your code introduce?

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[ ] Bugfix (non-breaking change which fixes an issue)
[ ] New feature (non-breaking change which adds functionality)
[ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist

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[ ] I have read the CONTRIBUTING doc
[ ] Lint and unit tests pass locally with my changes
[ ] I have added tests that prove my fix is effective or that my feature works.
[ ] I have added necessary documentation (if appropriate)

Further comments

If this is a relatively large or complex change, kick off the discussion by explaining why you chose the solution you did and what alternatives you considered, etc...

adonisjs / ally