fix java version

Author: MORIMORI0317

common/src/main/java/dev/felnull/fnjl/util/FNURLUtil.java

@@ -12,6 +12,7 @@
 import java.net.HttpURLConnection;
 import java.net.MalformedURLException;
 import java.net.URL;
+import java.util.HashMap;
 import java.util.Map;
 import java.util.Objects;
 import java.util.concurrent.CompletableFuture;
@@ -77,7 +78,7 @@ public static HttpURLConnection getConnection(@NotNull URL url, @NotNull Map<Str
      */
     @NotNull
     public static HttpURLConnection getConnection(@NotNull URL url) throws IOException {
-        return getConnection(url, Map.of());
+        return getConnection(url, new HashMap<>());
     }
 
     /**

settings.gradle

@@ -3,3 +3,6 @@ rootProject.name = 'FelNullJavaLibrary'
 include("common")
 include("natives")
 
+if (JavaVersion.current().ordinal() + 1 != 8)
+    throw new IllegalStateException("Java8使ってくれよな～頼むよ～")
+