[BUG] Fix no implicit conversion of nil into Array error

[bbarani]

What is the bug?

Running any command in project-tools displays no implicit conversion of nil into Array after getting the desired response.

How can one reproduce the bug?

1. Execute this command: ./bin/project --debug --no-cache maintainers stats --repo=opensearch-project/data-prepper
2. You will see the correct response along with this error: error: no implicit conversion of nil into Array

What is the expected behavior?

No errors are displayed in response

What is your host/environment?

Mac OS

Do you have any screenshots?

NA

Do you have any additional context?

./bin/project --debug --no-cache maintainers stats --repo=opensearch-project/data-prepper

As of 2024-04-10, 1 repos have 9 maintainers, where 11.1% (1/9) are external.
A total of 100.0% (1/1) of repos have at least one of 1 external maintainers.

error: no implicit conversion of nil into Array