Bring back CI badge

Author: sdeleuze

README.adoc

@@ -6,7 +6,7 @@
 :boot-dev-version: 2.4.0
 :documentation-url: https://repo.spring.io/{repository}/org/springframework/experimental/spring-graalvm-native-docs/{version}/spring-graalvm-native-docs-{version}.zip!
 
-image:https://img.shields.io/badge/{version}-documentation-blue.svg["{version} documentation", link="{documentation-url}/reference/index.html"]
+image:https://ci.spring.io/api/v1/teams/spring-graalvm-native/pipelines/spring-graalvm-native/badge["Build Status", link="https://ci.spring.io/teams/spring-graalvm-native/pipelines/spring-graalvm-native"] image:https://img.shields.io/badge/{version}-documentation-blue.svg["{version} documentation", link="{documentation-url}/reference/index.html"]
 
 Spring Native for https://www.graalvm.org[GraalVM] provides support for compiling Spring to native executables using
 https://www.graalvm.org/reference-manual/native-image/[native-image] compiler.