Bump assertj-core from 3.22.0 to 3.23.1 in /modules/r2dbc

Bumps [assertj-core](https://github.com/assertj/assertj-core) from 3.22.0 to 3.23.1.
- [Release notes](https://github.com/assertj/assertj-core/releases)
- [Commits](assertj/assertj@assertj-core-3.22.0...assertj-core-3.23.1)

---
updated-dependencies:
- dependency-name: org.assertj:assertj-core
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

modules/r2dbc/build.gradle

@@ -11,10 +11,10 @@ dependencies {
     api project(':testcontainers')
     api 'io.r2dbc:r2dbc-spi:0.8.1.RELEASE'
 
-    testImplementation 'org.assertj:assertj-core:3.22.0'
+    testImplementation 'org.assertj:assertj-core:3.23.1'
     testImplementation 'io.r2dbc:r2dbc-postgresql:0.8.12.RELEASE'
     testImplementation project(':postgresql')
 
     testFixturesImplementation 'io.projectreactor:reactor-core:3.4.18'
-    testFixturesImplementation 'org.assertj:assertj-core:3.14.0'
+    testFixturesImplementation 'org.assertj:assertj-core:3.23.1'
 }