do not need to used rc channel for python=3.13

Author: jcapriot

.github/workflows/python-package-conda.yml

@@ -39,7 +39,7 @@ jobs:
       uses: conda-incubator/setup-miniconda@v3
       with:
         python-version: ${{ matrix.python-version }}
-        channels: ${{ matrix.python-version == '3.13' && 'conda-forge/label/python_rc,conda-forge, ' || ''}}defaults
+        channels: conda-forge, defaults
         channel-priority: true
         activate-environment: dev