build: Only set features for x68-64

Author: ritchie46

.github/workflows/release-python.yml

@@ -76,6 +76,7 @@ jobs:
           [[ "$VERSION" == "${COMPAT_VERSION[2]}" ]] || (echo "Incorrect rtcompat version" && exit 1)
 
       - name: Update features in PLR
+        if: matrix.architecture == 'x86-64'
         env:
           PLR_PATH: py-polars/polars/_plr.py
         run: |