fix druid filter init bug

[hieastz]

filter->filters

What kind of change does this PR introduce? (check at least one)

• [x] Bugfix
• [ ] Feature
• [ ] Code style
• [ ] Refactor
• [ ] Doc
• [ ] Other, please describe:

The description of the PR: druid的拦截器名称配置属性是filters而不是filter，反射的时候是获取不到值的。

Other information: https://github.com/baomidou/dynamic-datasource/blob/master/dynamic-datasource-creator/src/main/java/com/baomidou/dynamic/datasource/creator/druid/DruidConfig.java

@Getter
@Setter
public class DruidConfig {

    private String filters;

}