Add spotbugs to testCompileOnly as well

* Add `com.github.spotbugs` into Dependabot dev group

.github/dependabot.yml

@@ -16,6 +16,7 @@ updates:
         update-types: ["patch"]
         patterns:
           - "com.gradle.enterprise"
+          - "com.github.spotbugs"
           - "io.spring.*"
           - "org.ajoberstar.grgit"
           - "org.antora"

build.gradle

@@ -256,7 +256,9 @@ configure(javaProjects) { subproject ->
             api project(':spring-integration-core')
         }
 
-        compileOnly "com.github.spotbugs:spotbugs-annotations:${spotbugs.toolVersion.get()}"
+        def spotbugsAnnotations = "com.github.spotbugs:spotbugs-annotations:${spotbugs.toolVersion.get()}"
+        compileOnly spotbugsAnnotations
+        testCompileOnly spotbugsAnnotations
 
         testImplementation("org.awaitility:awaitility:$awaitilityVersion") {
             exclude group: 'org.hamcrest'