Bump micronaut-spring from 2.1.1 to 3.1.0 (#348)

Bumps [micronaut-spring](https://github.com/micronaut-projects/micronaut-spring) from 2.1.1 to 3.1.0.
- [Release notes](https://github.com/micronaut-projects/micronaut-spring/releases)
- [Commits](micronaut-projects/micronaut-spring@v2.1.1...v3.1.0)

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

test-core/build.gradle

@@ -1,6 +1,6 @@
 dependencies {
     annotationProcessor "io.micronaut:micronaut-inject-java:$micronautVersion"
-    compileOnly "io.micronaut.spring:micronaut-spring:2.1.1"
+    compileOnly "io.micronaut.spring:micronaut-spring:3.1.0"
     compileOnly "io.micronaut:micronaut-http-server:$micronautVersion"
     compileOnly("org.spockframework:spock-core:$spockVersion") {
         exclude group: "org.codehaus.groovy", module: "groovy-all"