MINOR: Fix broken maven badge (#35)

### What changes were proposed in this pull request?

This PR aims to fix the broken maven badge.

### Why are the changes needed?

**BEFORE**

<img width="294" height="42" alt="Screenshot 2026-02-18 at 09 07 16" src="https://github.com/user-attachments/assets/b407ccbc-5673-4d38-9b9c-882f7a8cd899" />

**AFTER**

<img width="337" height="39" alt="Screenshot 2026-02-18 at 09 06 29" src="https://github.com/user-attachments/assets/0f92167b-4735-4fa4-bd4b-99420248c16f" />

### How was this patch tested?

Manual review.

### Was this patch authored or co-authored using generative AI tooling?

Generated-by: `Gemini 3 Pro (High)` on `Antigravity`

Author: dongjoon-hyun

README.md

@@ -38,7 +38,7 @@ This project includes ORC specifications and the protobuf definition.
 `Apache ORC Format 1.0.0` is designed to be used for `Apache ORC 2.0+`.
 
 Releases:
-* Maven Central: <a href="https://search.maven.org/#search%7Cga%7C1%7Cg%3A%22org.apache.orc%22">![Maven Central](https://maven-badges.herokuapp.com/maven-central/org.apache.orc/orc/badge.svg)</a>
+* Maven Central: <a href="https://search.maven.org/artifact/org.apache.orc/orc-format">![Maven Central](https://img.shields.io/maven-central/v/org.apache.orc/orc-format.svg)</a>
 * Downloads: <a href="https://orc.apache.org/downloads">Apache ORC downloads</a>
 * Release tags: <a href="https://github.com/apache/orc-format/releases">Apache ORC Format releases</a>
 * Plan: <a href="https://github.com/apache/orc-format/milestones">Apache ORC Format future release plan</a>