Bumps the minor group with 5 updates in the /backend directory:

| Package | From | To |
| --- | --- | --- |
| org.flywaydb:flyway-database-postgresql | `10.20.1` | `10.21.0` |
| [org.jetbrains.exposed:exposed-spring-boot-starter](https://github.com/JetBrains/Exposed) | `0.55.0` | `0.56.0` |
| [org.jetbrains.exposed:exposed-jdbc](https://github.com/JetBrains/Exposed) | `0.55.0` | `0.56.0` |
| [org.jetbrains.exposed:exposed-json](https://github.com/JetBrains/Exposed) | `0.55.0` | `0.56.0` |
| [org.jetbrains.exposed:exposed-kotlin-datetime](https://github.com/JetBrains/Exposed) | `0.55.0` | `0.56.0` |



Updates `org.flywaydb:flyway-database-postgresql` from 10.20.1 to 10.21.0

Updates `org.jetbrains.exposed:exposed-spring-boot-starter` from 0.55.0 to 0.56.0
- [Release notes](https://github.com/JetBrains/Exposed/releases)
- [Changelog](https://github.com/JetBrains/Exposed/blob/main/CHANGELOG.md)
- [Commits](JetBrains/Exposed@0.55.0...0.56.0)

Updates `org.jetbrains.exposed:exposed-jdbc` from 0.55.0 to 0.56.0
- [Release notes](https://github.com/JetBrains/Exposed/releases)
- [Changelog](https://github.com/JetBrains/Exposed/blob/main/CHANGELOG.md)
- [Commits](JetBrains/Exposed@0.55.0...0.56.0)

Updates `org.jetbrains.exposed:exposed-json` from 0.55.0 to 0.56.0
- [Release notes](https://github.com/JetBrains/Exposed/releases)
- [Changelog](https://github.com/JetBrains/Exposed/blob/main/CHANGELOG.md)
- [Commits](JetBrains/Exposed@0.55.0...0.56.0)

Updates `org.jetbrains.exposed:exposed-kotlin-datetime` from 0.55.0 to 0.56.0
- [Release notes](https://github.com/JetBrains/Exposed/releases)
- [Changelog](https://github.com/JetBrains/Exposed/blob/main/CHANGELOG.md)
- [Commits](JetBrains/Exposed@0.55.0...0.56.0)

---
updated-dependencies:
- dependency-name: org.flywaydb:flyway-database-postgresql
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: minor
- dependency-name: org.jetbrains.exposed:exposed-spring-boot-starter
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: minor
- dependency-name: org.jetbrains.exposed:exposed-jdbc
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: minor
- dependency-name: org.jetbrains.exposed:exposed-json
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: minor
- dependency-name: org.jetbrains.exposed:exposed-kotlin-datetime
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: minor
...

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