Add older mkl build contraint only (#3302)

Summary:
Similar to what we used to have here:
https://github.com/pytorch/test-infra/pull/3896/files

Pull Request resolved: https://github.com/pytorch/audio/pull/3302

Reviewed By: nateanl

Differential Revision: D45574845

Pulled By: atalman

fbshipit-source-id: 142c35dfd811a5f5c170dcd082bec8d055edd9cb

packaging/torchaudio/meta.yaml

@@ -19,7 +19,7 @@ requirements:
     - ninja
     - numpy>=1.11 # [py <= 39]
     - numpy>=1.21.2 # [py >= 310]
-    - mkl<=2021.4.0 # [osx and x86_64]
+    - mkl<=2021.2.0 # [osx and x86_64]
     - pytorch-mutex 1.0 {{ build_variant }}  # [not osx ]
     {{ environ.get('CONDA_PYTORCH_BUILD_CONSTRAINT', 'pytorch') }}
     {{ environ.get('CONDA_EXTRA_BUILD_CONSTRAINT', '') }}
@@ -30,7 +30,6 @@ requirements:
     - numpy>=1.11 # [py <= 39]
     - numpy>=1.21.2 # [py >= 310]
     - pytorch-mutex 1.0 {{ build_variant }}  # [not osx ]
-    - mkl<=2021.4.0 # [osx and x86_64]
     {{ environ.get('CONDA_PYTORCH_CONSTRAINT', 'pytorch') }}
     {{ environ.get('CONDA_CUDATOOLKIT_CONSTRAINT', '') }}