Fix broken link to changelogger

This commit addresses #3774 (comment)

CONTRIBUTING.md

@@ -34,7 +34,7 @@ To send us a pull request, please:
 2. Modify the source; please focus on the specific change you are contributing. If you also reformat all the code, it will be hard for us to focus on your change.
 3. Ensure local tests pass.
 4. Commit to your fork using clear commit messages.
-5. Send us a pull request, answering any default questions in the pull request interface. To create a changelog entry Markdown file in the `.changelog` directory, you can do so manually or use the [changelogger](https://github.com/smithy-lang/smithy-rs/tree/ysaito/switch-to-new-changelog-format/tools/ci-build/changelogger) CLI.
+5. Send us a pull request, answering any default questions in the pull request interface. To create a changelog entry Markdown file in the `.changelog` directory, you can do so manually or use the [changelogger](https://github.com/smithy-lang/smithy-rs/tree/main/tools/ci-build/changelogger) CLI.
 6. Pay attention to any automated CI failures reported in the pull request, and stay involved in the conversation.
 7. Ask maintainers to manually trigger [canary](https://github.com/smithy-lang/smithy-rs/actions/workflows/manual-canary.yml) and [PR bot](https://github.com/smithy-lang/smithy-rs/actions/workflows/manual-pull-request-bot.yml) workflows using your pull request number. Those workflows cannot run in your fork and are always skipped as such.