Bump peter-evans/create-pull-request from 5 to 6 (#8494)

Author: dependabot[bot]

.github/workflows/update-gpuci.yaml

@@ -54,7 +54,7 @@ jobs:
           regex: false
 
       - name: Create Pull Request
-        uses: peter-evans/create-pull-request@v5
+        uses: peter-evans/create-pull-request@v6
         if: ${{ env.UCX_PY_VER != env.NEW_UCX_PY_VER }}  # make sure new ucx-py nightlies are available
         with:
           token: ${{ secrets.GITHUB_TOKEN }}