Set compression lewel to -9

Signed-off-by: Graham <gpe@openrs2.org>

archive/src/main/kotlin/org/openrs2/archive/web/CachesController.kt

@@ -14,6 +14,7 @@ import org.openrs2.archive.cache.CacheExporter
 import org.openrs2.cache.DiskStoreZipWriter
 import java.nio.file.attribute.FileTime
 import java.time.Instant
+import java.util.zip.Deflater
 import java.util.zip.ZipEntry
 import java.util.zip.ZipOutputStream
 import javax.inject.Inject
@@ -93,6 +94,8 @@ public class CachesController @Inject constructor(
         call.respondOutputStream(contentType = ContentType.Application.Zip) {
             ZipOutputStream(this).use { output ->
                 output.bufferedWriter().use { writer ->
+                    output.setLevel(Deflater.BEST_COMPRESSION)
+
                     val timestamp = FileTime.from(Instant.EPOCH)
 
                     for (key in exporter.exportKeys(id)) {