Migrate librosa to the latest version

[MichaelTamaki]

The test suite stated that v. 1.6.1 is being used. We will need to check if the test suite still works with the latest version of Librosa if its available.

[MichaelTamaki]

Librosa v. 1.6.1 actually does not exist, the latest version available is 0.4.3. When I tried installing 1.6.1, I got:
Could not find a version that satisfies the requirement librosa==1.6.1 (from -r requirements.txt (line 3)) (from versions: 0.2.0.linux-x86_64, 0.2.1.linux-x86_64, 0.2.0, 0.2.1, 0.3.0, 0.3.1, 0.4.0rc2, 0.4.0, 0.4.1rc0, 0.4.1, 0.4.2, 0.4.3rc0, 0.4.3)
We will have to test which versions work, or implement the latest version.

[fatmai]

yeah, v.0.4.3 is the one we will use.

[MichaelTamaki]

While reading through the Feature Extraction Demo, https://github.com/machine-shop/music-features/blob/master/tutorials/FeatureExtraction.Demo.ipynb, I found that it says that Librosa v0.4.0 is used. I wonder what improvements were made thus far?