Update the torch version (#50)

Summary:
Pull Request resolved: #50

D48068293 had a breaking change. https://www.internalfb.com/phabricator/paste/view/P805891610

We need to update the torch version accordingly (also needs to update torchvision so that it is compatible with torch).

Reviewed By: angelayi

Differential Revision: D48188689

fbshipit-source-id: 849a9d38fabb54f7503547fb13bcb3a2ca5fa3e5

Author: mergennachin

.ci/docker/ci_commit_pins/pytorch.txt

@@ -1 +1 @@
-2.1.0.dev20230731
+2.1.0.dev20230809

docs/website/docs/tutorials/00_setting_up_executorch.md

@@ -24,7 +24,7 @@ Setting up PyTorch
 # Install the nightly builds
 # Note: if you are behind a firewall an appropriate proxy server must be setup
 # for all subsequent steps.
-TORCH_VERSION=2.1.0.dev20230731
+TORCH_VERSION=2.1.0.dev20230809
 pip install --force-reinstall --pre torch=="${TORCH_VERSION}" -i https://download.pytorch.org/whl/nightly/cpu
 ```
 

examples/install_requirements.sh

@@ -16,5 +16,5 @@
 # `TORCH_VISION_VERSION` value in this document will be the correct version for the
 # corresponsing version of the repo.
 
-TORCH_VISION_VERSION=0.16.0.dev20230731
+TORCH_VISION_VERSION=0.16.0.dev20230809
 pip install --force-reinstall --pre torchvision=="${TORCH_VISION_VERSION}" -i https://download.pytorch.org/whl/nightly/cpu