fix druid filter init bug

[hieastz]

filter->filters

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

• 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;

}