Check out <a href="http://pre-commit.com/" rel="nofollow">http://pre-commit.com/</a> with its "detect-aws-credentials"-hook, if you are serious about finding AWS credentials configured for AWS CLI/boto/etc. in your code.
"git-secrets" will only check "./aws/credentials" for configured AWS credentials and not all other locations (different files, environment variables) where such credentials might be configured.