Add explicit version of slf4j-api again

Gradle does not need it, because it comes from the dependencies of cyclonedx-core-java,
but the maven-publish plugin is not smart enough to put the inferred version into the POM.

Author: tsjensen

build.gradle

@@ -67,7 +67,7 @@ project.gradle.taskGraph.whenReady { taskGraph ->
 dependencies {
     compileOnly group: 'com.google.code.findbugs', name: 'jsr305', version: '3.0.2'
     api group: 'org.cyclonedx', name: 'cyclonedx-core-java', version: '10.2.1'
-    implementation group: 'org.slf4j', name: 'slf4j-api'
+    implementation group: 'org.slf4j', name: 'slf4j-api', version: '2.0.16'
 
     testCompileOnly group: 'com.google.code.findbugs', name: 'jsr305', version: '3.0.2'
     testImplementation group: 'junit', name: 'junit', version: '4.13.2'