[MLH Fellow] [Audio] Add loop augmentation

[zpapakipos]

🚀 Feature

Implement a new augmentation called loop which takes in an audio file/numpy array and returns it looped a given n number of times.

To do

• Read our contributing guidelines for all the steps to add a new augmentation
• Note: for this augmentation you will also need to define how the matching segments will change here. This should work similarly to how the segments are computed for the video loop augmentation here.
• Make sure the audio tests (including the new one you have added) pass: python -m unittest discover -s augly/tests/audio_tests/ -p "*"