Configure signing of publishing projects regardless of sonatype (#12)

It is needed when plugin publishing is configured using infra.
The plugin might be published only to Gradle Plugin Portal.

Author: Abduqodiri Qurbonzoda

main/src/kotlinx/team/infra/Publishing.kt

@@ -91,11 +91,16 @@ internal fun Project.configurePublishing(publishing: PublishingConfiguration) {
         if (verifySonatypeConfiguration()) {
             includeProjects.forEach { subproject ->
                 subproject.createSonatypeRepository()
-                subproject.configureSigning()
             }
         }
     }
 
+    if (project.hasProperty("teamcity")) {
+        includeProjects.forEach { subproject ->
+            subproject.configureSigning()
+        }
+    }
+
     gradle.includedBuilds.forEach { includedBuild ->
         logger.infra("Included build: ${includedBuild.name} from ${includedBuild.projectDir}")
         val includedPublishTask = includedBuild.task(":$compositeBuildLocal")

publish.gradle

@@ -1,7 +1,7 @@
 project.version = project.hasProperty('releaseVersion') ? project.property('releaseVersion') : project.version
 
 task sourceJar(type: Jar) {
-    classifier 'sources'
+    archiveClassifier.set("sources")
     from sourceSets.main.allJava.sourceDirectories
 }