Bump pl.allegro.tech.hermes:hermes-mock from 2.6.3 to 2.6.4

Bumps [pl.allegro.tech.hermes:hermes-mock](https://github.com/allegro/hermes) from 2.6.3 to 2.6.4.
- [Release notes](https://github.com/allegro/hermes/releases)
- [Changelog](https://github.com/allegro/hermes/blob/master/RELEASE_FLOW.md)
- [Commits](allegro/hermes@hermes-2.6.3...hermes-2.6.4)

---
updated-dependencies:
- dependency-name: pl.allegro.tech.hermes:hermes-mock
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

part2.3-message-broker/build.gradle

@@ -26,7 +26,7 @@ dependencies {
     testRuntimeOnly("org.junit.platform:junit-platform-launcher")
     testImplementation project(':commons')
     testImplementation project(':commons-rest')
-    testImplementation 'pl.allegro.tech.hermes:hermes-mock:2.6.3'
+    testImplementation 'pl.allegro.tech.hermes:hermes-mock:2.6.4'
     testImplementation 'org.spockframework:spock-spring:2.4-M4-groovy-4.0'
 }