Fix README for a new style of action invocation

Author: artembilan

README.adoc

@@ -72,18 +72,10 @@ jobs:
       pull-requests: write
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
-      - uses: actions/setup-java@v3
+      - name: Create Backport Issue
+        uses: spring-io/[email protected]
         with:
-          distribution: 'temurin'
-          java-version: '17'
-      - name: Download BackportBot
-        run: wget https://github.com/spring-io/backport-bot/releases/download/latest/backport-bot-0.0.1-SNAPSHOT.jar
-      - name: Backport
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-          GITHUB_EVENT: ${{ toJSON(github.event) }}
-        run: java -jar backport-bot-0.0.1-SNAPSHOT.jar --github.accessToken="$GITHUB_TOKEN" --github.event_name "$GITHUB_EVENT_NAME" --github.event "$GITHUB_EVENT"
+          token: ${{ secrets.GITHUB_TOKEN }}
 ----