Update peter-evans/create-pull-request action to v7

Author: renovate[bot]

.github/workflows/spm.yml

@@ -26,7 +26,7 @@ jobs:
           swift build
       - name: Create Pull Request
         id: cpr
-        uses: peter-evans/create-pull-request@v6
+        uses: peter-evans/create-pull-request@v7
         with:
           token: ${{ secrets.GH_PAT }}
           base: "master"