use a multiline comment

Author: TimHess

.github/workflows/build_springboot_admin_server.yaml

@@ -57,5 +57,9 @@ jobs:
                 issue_number: context.issue.number,
                 owner: context.repo.owner,
                 repo: context.repo.repo,
-                body: 'Run the Spring Boot Admin server image built for this PR: `docker run --rm -d --pull=always -p 9099:9099 --name spring-boot-admin-pr steeltoe.azurecr.io/spring-boot-admin:pr-${{ github.event.number }}`'
+                body: '
+                    To run the Spring Boot Admin server image built for this PR:
+                    ```bash
+                    docker run --rm -d --pull=always -p 9099:9099 --name spring-boot-admin-pr steeltoe.azurecr.io/spring-boot-admin:pr-${{ github.event.number }}
+                    ```'
             })