Bump flinkVersion from 1.15.1 to 1.15.2 (#1)

Bumps `flinkVersion` from 1.15.1 to 1.15.2.

Updates `flink-java` from 1.15.1 to 1.15.2
- [Release notes](https://github.com/apache/flink/releases)
- [Commits](apache/flink@release-1.15.1...release-1.15.2)

Updates `flink-test-utils-junit` from 1.15.1 to 1.15.2

---
updated-dependencies:
- dependency-name: org.apache.flink:flink-java
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: org.apache.flink:flink-test-utils-junit
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

build.gradle.kts

@@ -16,7 +16,7 @@ repositories {
 dependencies {
     implementation(kotlin("reflect"))
 
-    val flinkVersion = "1.15.1"
+    val flinkVersion = "1.15.2"
     implementation("org.apache.flink:flink-java:$flinkVersion")
 
     testImplementation("org.apache.flink:flink-test-utils-junit:$flinkVersion")