Bumps [spring-core](https://github.com/spring-projects/spring-framework) from 5.3.2 to 5.3.20.
- [Release notes](https://github.com/spring-projects/spring-framework/releases)
- [Commits](https://github.com/spring-projects/spring-framework/compare/v5.3.2...v5.3.20)

---
updated-dependencies:
- dependency-name: org.springframework:spring-core
  dependency-type: direct:production
...
Signed-off-by: Ndependabot[bot] <support@github.com>
Signed-off-by: Ndependabot[bot] <support@github.com>
Co-authored-by: Ndependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Shuduo Sang <sangshuduo@gmail.com>