Fix license check CI failure

[multiplemonomials]

Summary of changes

This fixes the license check CI failing due to aboutcode-org/scancode-toolkit#3160 .

Impact of changes

Migration actions required

Documentation

None

Pull request type

[X] Patch update (Bug fix / Target update / Docs update / Test update / Refactor)
[] Feature update (New feature / Functionality change / New API)
[] Major update (Breaking change E.g. Return code change / API behaviour change)

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Test results

[] No Tests required for this change (E.g docs only update)
[X] Covered by existing mbed-os tests (Greentea or Unittest)
[] Tests / results supplied as part of this PR

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Reviewers

@JojoS62
@JohnK1987

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[pombredanne]

@multiplemonomials sorry for introducinng this bug! I pushed a fix in gemfileparser2 per aboutcode-org/scancode-toolkit#3160 (comment)

fixed by pushing a fix for backward compat to https://github.com/nexB/gemfileparser2/releases/tag/v0.9.3