Additional replacement patterns

Suggested by @mathiasbynens in #12:

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Other possible replacements (you'd probably want to do these globally, in all files):

- `https://github.com///tree/` ([example](https://github.com/mheap/github-default-branch/tree/main/src))
- `https://github.com///blob/` ([example](https://github.com/mheap/github-default-branch/blob/main/src/get-repos.js))
- `https://raw.githubusercontent.com///` ([example](https://raw.githubusercontent.com/mheap/github-default-branch/main/src/get-repos.js))

No file or test is named; inspect the repository for the existing replacement logic related to issue #12 and identify the CLI entry point and all affected files. Add support for the listed GitHub tree, blob, and raw URL patterns globally, then verify that each example URL is rewritten to the default branch.

Written by the indexing model from the issue text.