Allow for .yml trufflehog config files

Currently, when a trufflehog finding needs to be whitelisted, a trufflehog-config.yaml file needs to be created to list the files and patterns within files, to be ignored. If someone were to create a trufflehog-config with a .yml file extension, it would not be used to create a config, and may even cause additional findings.

Acceptance Criteria

• trufflehog.py is updated to import trufflehog-config files with both .yaml and .yml extensions