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.

gradle.properties

@@ -1,4 +1,4 @@
-group = "io.papermc.paper"
+group = io.papermc.paper
 version = 1.17-R0.1-SNAPSHOT
 
 mcVersion = 1.17

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

@@ -20,6 +20,8 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 --- /dev/null
 +++ b/build.gradle.kts
 @@ -0,0 +0,0 @@
++import java.util.Locale
++
 +plugins {
 +    `java-library`
 +    checkstyle
@@ -53,7 +55,18 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +    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"