Bump testcontainers from 1.18.3 to 1.19.0 in /reposilite-backend

Bumps `testcontainers` from 1.18.3 to 1.19.0.

Updates `org.testcontainers:postgresql` from 1.18.3 to 1.19.0
- [Release notes](https://github.com/testcontainers/testcontainers-java/releases)
- [Changelog](https://github.com/testcontainers/testcontainers-java/blob/main/CHANGELOG.md)
- [Commits](testcontainers/testcontainers-java@1.18.3...1.19.0)

Updates `org.testcontainers:mariadb` from 1.18.3 to 1.19.0
- [Release notes](https://github.com/testcontainers/testcontainers-java/releases)
- [Changelog](https://github.com/testcontainers/testcontainers-java/blob/main/CHANGELOG.md)
- [Commits](testcontainers/testcontainers-java@1.18.3...1.19.0)

Updates `org.testcontainers:testcontainers` from 1.18.3 to 1.19.0
- [Release notes](https://github.com/testcontainers/testcontainers-java/releases)
- [Changelog](https://github.com/testcontainers/testcontainers-java/blob/main/CHANGELOG.md)
- [Commits](testcontainers/testcontainers-java@1.18.3...1.19.0)

Updates `org.testcontainers:junit-jupiter` from 1.18.3 to 1.19.0
- [Release notes](https://github.com/testcontainers/testcontainers-java/releases)
- [Changelog](https://github.com/testcontainers/testcontainers-java/blob/main/CHANGELOG.md)
- [Commits](testcontainers/testcontainers-java@1.18.3...1.19.0)

Updates `org.testcontainers:localstack` from 1.18.3 to 1.19.0
- [Release notes](https://github.com/testcontainers/testcontainers-java/releases)
- [Changelog](https://github.com/testcontainers/testcontainers-java/blob/main/CHANGELOG.md)
- [Commits](testcontainers/testcontainers-java@1.18.3...1.19.0)

Updates `org.testcontainers:mysql` from 1.18.3 to 1.19.0
- [Release notes](https://github.com/testcontainers/testcontainers-java/releases)
- [Changelog](https://github.com/testcontainers/testcontainers-java/blob/main/CHANGELOG.md)
- [Commits](testcontainers/testcontainers-java@1.18.3...1.19.0)

---
updated-dependencies:
- dependency-name: org.testcontainers:postgresql
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: org.testcontainers:mariadb
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: org.testcontainers:testcontainers
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: org.testcontainers:junit-jupiter
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: org.testcontainers:localstack
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: org.testcontainers:mysql
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

reposilite-backend/build.gradle.kts

@@ -121,7 +121,7 @@ dependencies {
     implementation("org.tinylog:tinylog-api:$tinylog")
     implementation("org.tinylog:tinylog-impl:$tinylog")
 
-    val testcontainers = "1.18.3"
+    val testcontainers = "1.19.0"
     testImplementation("org.testcontainers:postgresql:$testcontainers")
     testImplementation("org.testcontainers:mariadb:$testcontainers")
     testImplementation("org.testcontainers:testcontainers:$testcontainers")