Update repositories.txt

[github-actions[bot]]

Hi @rgot-org. Your pull request has been detected as something other than a Library Manager submission. A maintainer will need to review it before it can be merged.

If you intended to submit a library, please check the instructions and update your pull request if necessary: https://github.com/arduino/library-registry/blob/main/README.md#instructions

[github-actions[bot]]

A problem was found with your submission https://github.com/Nat/birdhouse_sdk

:x: ERROR: Unable to load submission URL. Is the repository public?

[github-actions[bot]]

Thanks for your interest in contributing to the Arduino Library Manager index @rgot-org Please resolve the error(s) mentioned in the previous comment.

After resolving the issue, trigger this check again by doing one of the following:

• Commit the required change to the branch you submitted this pull request from.
• Comment here, mentioning @ArduinoBot in the comment.

:exclamation: NOTE: It is not necessary to open a new pull request. :exclamation:

More information: https://github.com/arduino/library-registry/blob/main/README.md#if-the-problem-is-with-the-pull-request