Bump maven.api.version from 3.9.3 to 3.9.4 (#592)

Bumps `maven.api.version` from 3.9.3 to 3.9.4.

Updates `org.apache.maven:maven-core` from 3.9.3 to 3.9.4
- [Release notes](https://github.com/apache/maven/releases)
- [Commits](apache/maven@maven-3.9.3...maven-3.9.4)

Updates `org.apache.maven:maven-artifact` from 3.9.3 to 3.9.4
- [Release notes](https://github.com/apache/maven/releases)
- [Commits](apache/maven@maven-3.9.3...maven-3.9.4)

Updates `org.apache.maven:maven-plugin-api` from 3.9.3 to 3.9.4
- [Release notes](https://github.com/apache/maven/releases)
- [Commits](apache/maven@maven-3.9.3...maven-3.9.4)

---
updated-dependencies:
- dependency-name: org.apache.maven:maven-core
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: org.apache.maven:maven-artifact
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: org.apache.maven:maven-plugin-api
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

boat-maven-plugin/pom.xml

@@ -15,7 +15,7 @@
     <description>Open API Converter</description>
 
     <properties>
-        <maven.api.version>3.9.3</maven.api.version>
+        <maven.api.version>3.9.4</maven.api.version>
         <sonar.coverage.exclusions>
             src/main/java/com/backbase/oss/boat/GenerateMojo.java,
             src/main/java/com/backbase/oss/codegen/*.java