Bump springBootVersion from 2.2.6.RELEASE to 2.3.3.RELEASE

Bumps `springBootVersion` from 2.2.6.RELEASE to 2.3.3.RELEASE.

Updates `spring-boot-gradle-plugin` from 2.2.6.RELEASE to 2.3.3.RELEASE
- [Release notes](https://github.com/spring-projects/spring-boot/releases)
- [Commits](spring-projects/spring-boot@v2.2.6.RELEASE...v2.3.3.RELEASE)

Updates `spring-boot-starter-web` from 2.2.6.RELEASE to 2.3.3.RELEASE
- [Release notes](https://github.com/spring-projects/spring-boot/releases)
- [Commits](spring-projects/spring-boot@v2.2.6.RELEASE...v2.3.3.RELEASE)

Updates `spring-boot-starter-data-jpa` from 2.2.6.RELEASE to 2.3.3.RELEASE
- [Release notes](https://github.com/spring-projects/spring-boot/releases)
- [Commits](spring-projects/spring-boot@v2.2.6.RELEASE...v2.3.3.RELEASE)

Updates `spring-boot-starter-json` from 2.2.6.RELEASE to 2.3.3.RELEASE
- [Release notes](https://github.com/spring-projects/spring-boot/releases)
- [Commits](spring-projects/spring-boot@v2.2.6.RELEASE...v2.3.3.RELEASE)

Updates `spring-boot-starter-actuator` from 2.2.6.RELEASE to 2.3.3.RELEASE
- [Release notes](https://github.com/spring-projects/spring-boot/releases)
- [Commits](spring-projects/spring-boot@v2.2.6.RELEASE...v2.3.3.RELEASE)

Updates `spring-boot-starter-test` from 2.2.6.RELEASE to 2.3.3.RELEASE
- [Release notes](https://github.com/spring-projects/spring-boot/releases)
- [Commits](spring-projects/spring-boot@v2.2.6.RELEASE...v2.3.3.RELEASE)

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

Author: dependabot-preview[bot]

build.gradle

@@ -1,7 +1,7 @@
 buildscript {
     ext {
         kotlinVersion = '1.3.72'
-        springBootVersion = '2.2.6.RELEASE'
+        springBootVersion = '2.3.3.RELEASE'
         jacksonVersion = '2.11.2'
         javaVersion = '1.8' // https://stackoverflow.com/a/52890377
         swaggerVersion = '3.0.0'