fixed duplicate packages in Cargo.lock

[anpin]

Description

Fixed duplicate test-generator entry in the Cargo.lock which was failing cargo vendor with error below, which in turn was preventing me from wrapping the extension for nixos because of NixOS/nixpkgs#30742

Error message

error: failed to sync

Caused by:
  found duplicate version of package `test-generator v0.3.0` vendored from two sources:

        source 1: registry `crates-io`
        source 2: https://github.com/JamesGuthrie/test-generator#82e79997 

Merge requirements

Please take into account the following non-code changes that you may need to make with your PR:

• CHANGELOG entry for user-facing changes
• Updated the relevant documentation

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