Fix CI job to update nightly version (#1204)

make job push PR to wasmi repo

.github/workflows/update-nightly.yml

@@ -30,15 +30,31 @@ jobs:
           LATEST_NIGHTLY=$(echo $RUSTC_VERSION | grep -Po '\d{4}-\d{2}-\d{2}')
           echo "LATEST_NIGHTLY=$LATEST_NIGHTLY" >> $GITHUB_ENV
 
+      - name: Create new branch
+        run: |
+          git checkout -b update-rust-nightly-$LATEST_NIGHTLY
+  
       - name: Update nightly version in CI workflow
         run: |
           FILE=".github/workflows/rust.yml"
           sed -i "s/toolchain: nightly-[0-9]\{4\}-[0-9]\{2\}-[0-9]\{2\}/toolchain: nightly-$LATEST_NIGHTLY/" $FILE
 
-      - name: Commit and push changes
+      - name: Commit changes
         run: |
           git config --local user.email "github-actions[bot]@users.noreply.github.com"
           git config --local user.name "github-actions[bot]"
           git add .github/workflows/rust.yml
           git commit -m "Update Rust nightly version to $LATEST_NIGHTLY"
-          git push
+  
+      - name: Push changes to new branch
+        run: |
+          git push origin update-rust-nightly-$LATEST_NIGHTLY
+  
+      - name: Create Pull Request
+        uses: peter-evans/create-pull-request@v5
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+          branch: update-rust-nightly-$LATEST_NIGHTLY
+          title: "CI: Update Rust nightly version to $LATEST_NIGHTLY"
+          body: "This PR updates the Rust nightly version to $LATEST_NIGHTLY."
+          base: main