update README.md

RuoYi

2021-01-14 99390fda05f53af18a07a3ba5194bada39a54716

 ruoyi-common/ruoyi-common-core/src/main/java/com/ruoyi/common/core/utils/SecurityUtils.java

@@ -17,7 +17,8 @@
     */
    public static String getUsername()
    {
        return ServletUtils.getRequest().getHeader(CacheConstants.DETAILS_USERNAME);
        String username = ServletUtils.getRequest().getHeader(CacheConstants.DETAILS_USERNAME);
        return ServletUtils.urlDecode(username);
    }

    /**