improve installing nightly pytorch (#2026)

Summary:
Similar to https://github.com/pytorch/vision/pull/4788
Make sure the workflow could download right PyTorch with cpu or cuda in case nightly build wasn't ready at that day.

https://app.circleci.com/pipelines/github/pytorch/audio/8427/workflows/11a80738-bcdd-45e3-b37f-328be36c60ee/jobs/438285?invite=true#step-107-542

![image](https://user-images.githubusercontent.com/16190118/142969390-142df7ec-6040-40c1-9a02-17d43f5de05e.png)

Pull Request resolved: https://github.com/pytorch/audio/pull/2026

Reviewed By: hwangjeff, nateanl

Differential Revision: D32634926

Pulled By: mthrok

fbshipit-source-id: 30d6349a0a2ce174b789a5888b1c8e0544a23a37

.circleci/unittest/linux/scripts/install.sh

@@ -29,21 +29,25 @@ if [ -z "${CUDA_VERSION:-}" ] ; then
     else
         cudatoolkit="cpuonly"
     fi
+    version="cpu"
 else
     version="$(python -c "print('.'.join(\"${CUDA_VERSION}\".split('.')[:2]))")"
     cudatoolkit="cudatoolkit=${version}"
 fi
+
 printf "Installing PyTorch with %s\n" "${cudatoolkit}"
 (
     if [ "${os}" == MacOSX ] ; then
       # TODO: this can be removed as soon as linking issue could be resolved
       #  see https://github.com/pytorch/pytorch/issues/62424 from details
       MKL_CONSTRAINT='mkl==2021.2.0'
+      pytorch_build=pytorch
     else
       MKL_CONSTRAINT=''
+      pytorch_build="pytorch[build="*${version}*"]"
     fi
     set -x
-    conda install ${CONDA_CHANNEL_FLAGS:-} -y -c "pytorch-${UPLOAD_CHANNEL}" $MKL_CONSTRAINT "pytorch-${UPLOAD_CHANNEL}::pytorch" ${cudatoolkit}
+    conda install ${CONDA_CHANNEL_FLAGS:-} -y -c "pytorch-${UPLOAD_CHANNEL}" $MKL_CONSTRAINT "pytorch-${UPLOAD_CHANNEL}::${pytorch_build}" ${cudatoolkit}
 )
 
 # 2. Install torchaudio

.circleci/unittest/windows/scripts/install.sh

@@ -23,12 +23,13 @@ source "$this_dir/set_cuda_envs.sh"
 # 1. Install PyTorch
 if [ -z "${CUDA_VERSION:-}" ] ; then
     cudatoolkit="cpuonly"
+    version="cpu"
 else
     version="$(python -c "print('.'.join(\"${CUDA_VERSION}\".split('.')[:2]))")"
     cudatoolkit="cudatoolkit=${version}"
 fi
 printf "Installing PyTorch with %s\n" "${cudatoolkit}"
-conda install -y -c "pytorch-${UPLOAD_CHANNEL}" -c conda-forge "pytorch-${UPLOAD_CHANNEL}"::pytorch "${cudatoolkit}" pytest
+conda install -y -c "pytorch-${UPLOAD_CHANNEL}" -c conda-forge "pytorch-${UPLOAD_CHANNEL}"::pytorch[build="*${version}*"] "${cudatoolkit}" pytest
 
 torch_cuda=$(python -c "import torch; print(torch.cuda.is_available())")
 echo torch.cuda.is_available is $torch_cuda