Bump testcontainers from 1.15.2 to 1.15.3 in /core (#4067)

Bumps [testcontainers](https://github.com/testcontainers/testcontainers-java) from 1.15.2 to 1.15.3.
- [Release notes](https://github.com/testcontainers/testcontainers-java/releases)
- [Changelog](https://github.com/testcontainers/testcontainers-java/blob/master/CHANGELOG.md)
- [Commits](1.15.2...1.15.3)

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

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

Author: dependabot[bot]

core/build.gradle

@@ -165,7 +165,7 @@ configurations.all {
 }
 
 dependencies {
-    baseline 'org.testcontainers:testcontainers:1.15.2', {
+    baseline 'org.testcontainers:testcontainers:1.15.3', {
         exclude group: "*", module: "*"
     }