Update librosa/numba in CI (#864)

librosa 0.8.0 has been released which include fix for
https://github.com/librosa/librosa/issues/1160 at
https://github.com/librosa/librosa/pull/1164

.circleci/unittest/linux/scripts/environment.yml

@@ -8,11 +8,10 @@ dependencies:
   - pytest-cov
   - pytest-xdist
   - codecov
-  - librosa
+  - librosa>=0.8.0
   - llvmlite==0.31  # See https://github.com/pytorch/audio/pull/766
   - pip
   - pip:
     - kaldi-io
     - scipy
     - parameterized
-    - numba==0.48  # See https://github.com/librosa/librosa/issues/1160

.circleci/unittest/windows/scripts/environment.yml

@@ -12,7 +12,6 @@ dependencies:
     - scipy == 1.4.1
     - kaldi-io
     - PySoundFile
-    - librosa
+    - librosa >= 0.8.0
     - future
     - parameterized
-    - numba==0.48