Fix cuda version in nightly (#1261)

Author: atalman

conda/build_pytorch.sh

@@ -266,7 +266,7 @@ else
     # TODO, simplify after anaconda fixes their cudatoolkit versioning inconsistency.
     # see: https://github.com/conda-forge/conda-forge.github.io/issues/687#issuecomment-460086164
     if [[ "$desired_cuda" == "11.8" ]]; then
-        export CONDA_CUDATOOLKIT_CONSTRAINT="    - pytorch-cuda >=11.9,<12.0 # [not osx]"
+        export CONDA_CUDATOOLKIT_CONSTRAINT="    - pytorch-cuda >=11.8,<11.9 # [not osx]"
         export MAGMA_PACKAGE="    - magma-cuda118 # [not osx and not win]"
     elif [[ "$desired_cuda" == "11.7" ]]; then
         export CONDA_CUDATOOLKIT_CONSTRAINT="    - pytorch-cuda >=11.7,<11.8 # [not osx]"