remove fvcore dependency

Summary: This is not actually needed and is causing a conda-forge confusion to do with python_abi - which needs users to have `-c conda-forge` when they install pytorch3d.

Reviewed By: patricklabatut

Differential Revision: D59587930

fbshipit-source-id: 961ae13a62e1b2b2ce6d8781db38bd97eca69e65

packaging/linux_wheels/README.md

@@ -26,6 +26,6 @@ version_str="".join([
     torch.version.cuda.replace(".",""),
     f"_pyt{pyt_version_str}"
 ])
-!pip install fvcore iopath
+!pip install iopath
 !pip install --no-index --no-cache-dir pytorch3d -f https://dl.fbaipublicfiles.com/pytorch3d/packaging/wheels/{version_str}/download.html
 ```

packaging/linux_wheels/inside.sh

@@ -144,7 +144,7 @@ do
             conda activate "$tag"
             # shellcheck disable=SC2086
             conda install -y -c pytorch $extra_channel "pytorch=$pytorch_version" "$cudatools=$CUDA_TAG"
-            pip install fvcore iopath
+            pip install iopath
             echo "python version" "$python_version" "pytorch version" "$pytorch_version" "cuda version" "$cu_version" "tag" "$tag"
 
             rm -rf dist