Update test_stable.yml

.github/workflows/test_stable.yml

@@ -65,6 +65,8 @@ jobs:
         python setup.py egg_info
         req_txt="botorch.egg-info/requires.txt"
         min_torch_version=$(grep '\btorch[>=]=' ${req_txt} | sed 's/[^0-9.]//g')
+        # The earliest PyTorch version on Python 3.12 is 2.2.0.
+        min_torch_version="$(if ${{ matrix.python-version == '3.12' }}; then echo "2.2.0"; else echo "${min_torch_version}"; fi)"
         min_gpytorch_version=$(grep '\bgpytorch[>=]=' ${req_txt} | sed 's/[^0-9.]//g')
         min_linear_operator_version=$(grep '\blinear_operator[>=]=' ${req_txt} | sed 's/[^0-9.]//g')
         pip install "torch==${min_torch_version}" "gpytorch==${min_gpytorch_version}" "linear_operator==${min_linear_operator_version}"