fix: runtime header value

Author: matoous

src/main/java/com/sumup/sdk/core/SdkMetadata.java

@@ -25,7 +25,7 @@ public final class SdkMetadata {
           "X-Sumup-Package-Version", VERSION,
           "X-Sumup-OS", System.getProperty("os.name", "unknown"),
           "X-Sumup-Arch", runtimeArch(),
-          "X-Sumup-Runtime", runtimeIdentifier(),
+          "X-Sumup-Runtime", LANGUAGE,
           "X-Sumup-Runtime-Version", Runtime.version().toString());
 
   private SdkMetadata() {}
@@ -61,10 +61,6 @@ static String runtimeArch() {
     };
   }
 
-  private static String runtimeIdentifier() {
-    return LANGUAGE + Runtime.version();
-  }
-
   private static String loadResource(String path) {
     try (InputStream stream = SdkMetadata.class.getResourceAsStream(path)) {
       if (stream == null) {