Add important callout in README for colima users

[drewble]

Description

Update the "Adding a new SDK" section README to include a critical note for developers using Colima to run docker.

References

Review Checklist

• I have clicked on "allow edits by maintainers".
• I have added documentation for new/changed functionality in this PR or in a PR to openfga.dev [Provide a link to any relevant PRs in the references section above]
• The correct base branch is being used, if not main
• I have added tests to validate that the change in functionality is working as expected

[linux-foundation-easycla]

• ❌ - login: @drewble . The commit (00f3be0) is not authorized under a signed CLA. Please click here to be authorized. For further assistance with EasyCLA, please submit a support request ticket.

[rhamzeh]

@drewble - may I ask if you can sign the Linux Foundation's/CNCF's EasyCLA above? #458 (comment)