bukkit: Add run tasks for testing legacy versions

examples/example-bukkit/build.gradle.kts

@@ -1,3 +1,5 @@
+import xyz.jpenilla.runpaper.task.RunServerTask
+
 plugins {
     id("cloud.example-conventions")
     id("com.github.johnrengelman.shadow")
@@ -27,5 +29,32 @@ tasks {
     }
     runServer {
         minecraftVersion("1.17")
+        javaLauncher.set(project.javaToolchains.launcherFor {
+            languageVersion.set(JavaLanguageVersion.of(16))
+        })
+    }
+
+    // Setup a run task for each supported version
+    mapOf(
+            setOf("1.8.8", "1.9.4", "1.10.2", "1.11.2", "1.12.2") to 8,
+            setOf("1.13.2", "1.14.4", "1.15.2") to 11,
+            setOf("1.16.5", "1.17") to 16
+    ).forEach { (minecraftVersions, javaVersion) ->
+        for (version in minecraftVersions) {
+            createVersionedRun(version, javaVersion)
         }
     }
+}
+
+fun TaskContainerScope.createVersionedRun(
+        version: String,
+        javaVersion: Int
+) = register<RunServerTask>("runServer${version.replace(".", "")}") {
+    group = "cloud"
+    pluginJars.from(shadowJar.flatMap { it.archiveFile })
+    minecraftVersion(version)
+    runDirectory(file("run$version"))
+    javaLauncher.set(project.javaToolchains.launcherFor {
+        languageVersion.set(JavaLanguageVersion.of(javaVersion))
+    })
+}