Update README.md

Author: StephenHodgson

README.md

@@ -18,7 +18,7 @@ steps:
     with:
       project-path: '/path/to/your/build/output/directory'
       app-store-connect-key: ${{ secrets.APP_STORE_CONNECT_KEY }}
-      app-store-connect-key-id: ${{ secrets.APP_STORE_CONNECT_KEY }}
+      app-store-connect-key-id: ${{ secrets.APP_STORE_CONNECT_KEY_ID }}
       app-store-connect-issuer-id: ${{ secrets.APP_STORE_CONNECT_ISSUER_ID }}
       team-id: ${{ secrets.APPLE_TEAM_ID }}