Write API version to pom.properties for Versioning to read

Maven writes this metadata normally, but we don't use maven. Maybe should modify Versioning instead in the future, but this works just fine for now.

patches/api/0001-Convert-project-to-Gradle.patch

@@ -16,10 +16,12 @@ index e431e3435737e28394d81b56568a08b3c3148b9b..c484aff2c192bf42059b5689327909e4
  /.project
 diff --git a/build.gradle.kts b/build.gradle.kts
 new file mode 100644
-index 0000000000000000000000000000000000000000..a0f1c1d1ac63fdcce942922ffe68a8d44c712513
+index 0000000000000000000000000000000000000000..f3dd92e136a71aa39e422de7b2c5f2f3fdec554e
 --- /dev/null
 +++ b/build.gradle.kts
-@@ -0,0 +1,54 @@
+@@ -0,0 +1,67 @@
++import java.util.Locale
++
 +plugins {
 +    `java-library`
 +    checkstyle
@@ -53,7 +55,18 @@ index 0000000000000000000000000000000000000000..a0f1c1d1ac63fdcce942922ffe68a8d4
 +    checkstyle("com.puppycrawl.tools:checkstyle:8.39")
 +}
 +
++val generateApiVersioningFile by tasks.registering {
++    val pomProps = layout.buildDirectory.file("pom.properties")
++    outputs.file(pomProps)
++    doLast {
++        pomProps.get().asFile.writeText("version=${project.version}")
++    }
++}
++
 +tasks.jar {
++    from(generateApiVersioningFile.map { it.outputs.files.singleFile }) {
++        into("META-INF/maven/${project.group}/${project.name.toLowerCase(Locale.ENGLISH)}")
++    }
 +    manifest {
 +        attributes += mapOf(
 +            "Automatic-Module-Name" to "org.bukkit"