Fix previous versions conda installation instructions

Author: atalman

_get_started/previous-versions.md

@@ -32,9 +32,9 @@ conda install pytorch==1.13.1 torchvision==0.14.1 torchaudio==0.13.1 -c pytorch
 
 ```
 # CUDA 11.6
-conda install pytorch==1.13.1 torchvision==0.14.1 torchaudio==0.13.1 pytorch-cuda=11.6 -c pytorch -nvidia
+conda install pytorch==1.13.1 torchvision==0.14.1 torchaudio==0.13.1 pytorch-cuda=11.6 -c pytorch -c nvidia
 # CUDA 11.7
-conda install pytorch==1.13.1 torchvision==0.14.1 torchaudio==0.13.1 pytorch-cuda=11.7 -c pytorch -nvidia
+conda install pytorch==1.13.1 torchvision==0.14.1 torchaudio==0.13.1 pytorch-cuda=11.7 -c pytorch -c nvidia
 # CPU Only
 conda install pytorch==1.13.1 torchvision==0.14.1 torchaudio==0.13.1 cpuonly -c pytorch
 ```
@@ -76,9 +76,9 @@ conda install pytorch==1.13.0 torchvision==0.14.0 torchaudio==0.13.0 -c pytorch
 
 ```
 # CUDA 11.6
-conda install pytorch==1.13.0 torchvision==0.14.0 torchaudio==0.13.0 pytorch-cuda=11.6 -c pytorch -nvidia
+conda install pytorch==1.13.0 torchvision==0.14.0 torchaudio==0.13.0 pytorch-cuda=11.6 -c pytorch -c nvidia
 # CUDA 11.7
-conda install pytorch==1.13.0 torchvision==0.14.0 torchaudio==0.13.0 pytorch-cuda=11.7 -c pytorch -nvidia
+conda install pytorch==1.13.0 torchvision==0.14.0 torchaudio==0.13.0 pytorch-cuda=11.7 -c pytorch -c nvidia
 # CPU Only
 conda install pytorch==1.13.0 torchvision==0.14.0 torchaudio==0.13.0 cpuonly -c pytorch
 ```