Bump spring-boot-starter-parent from 2.3.5.RELEASE to 2.4.0 (#25)

Bumps [spring-boot-starter-parent](https://github.com/spring-projects/spring-boot) from 2.3.5.RELEASE to 2.4.0.
- [Release notes](https://github.com/spring-projects/spring-boot/releases)
- [Commits](spring-projects/spring-boot@v2.3.5.RELEASE...v2.4.0)

Signed-off-by: dependabot-preview[bot] <[email protected]>

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Author: dependabot-preview[bot]

pom.xml

@@ -5,7 +5,7 @@
     <parent>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-parent</artifactId>
-        <version>2.3.5.RELEASE</version>
+        <version>2.4.0</version>
         <relativePath/> <!-- lookup parent from repository -->
     </parent>
     <groupId>de.filefighter</groupId>