Update the libraries

[Shryne]

The libraries should be updated. For example:

        <spring.version>5.1.15.RELEASE</spring.version>
        <spring-boot.version>2.1.14.RELEASE</spring-boot.version>

The current version of Spring Boot is 2.5.4 and the current version of Spring is 5.3.9.

Additionally, it seems like you don't answer to issues. If you have another system, you should mention it in the README and close the issue system in github.