The script does the following things:
  - 1. Run the build without Bzlmod enabled to generate resolved external
    dependencies with --experimental_repository_resolved_file
  - 2. Run the build with Bzlmod enabled and identify recongnized error message
  - 3. Use the resolved external deps info to give migration suggestions.
  - 4. Repeat 2 and 3 until all external deps are available via Bzlmod (or WORKSPACE.bzlmod).

To start the migration, clone the Bazel central registry repo and run the following command from your project root:
```
<path to a local BCR repo>/tools/migrate_to_bzlmod.py <build flags> <build targets>
```