fix(pigx-codegen): 修改代码生成默认分支为 master

- 将默认分支从 202601 调整为 master，避免生成代码时指向不存在的分支

(cherry picked from commit 0a86a2d9d012198c55ae77a423396ce709498703)

pigx-visual/pigx-codegen/src/main/java/com/pig4cloud/pigx/codegen/config/PigxCodeGenDefaultProperties.java

@@ -26,9 +26,9 @@ public class PigxCodeGenDefaultProperties implements InitializingBean {
     private boolean autoCheckVersion = false;
 
     /**
-     * 分支名称，默认为 202601
+     * 分支名称，默认为 master
      */
-    private String branch = "202601";
+    private String branch = "master";
 
 	/**
 	 * 模板项目地址