Bump com.google.firebase:firebase-admin in /push-sender

Bumps [com.google.firebase:firebase-admin](https://github.com/firebase/firebase-admin-java) from 9.5.0 to 9.6.0.
- [Release notes](https://github.com/firebase/firebase-admin-java/releases)
- [Commits](firebase/firebase-admin-java@v9.5.0...v9.6.0)

---
updated-dependencies:
- dependency-name: com.google.firebase:firebase-admin
  dependency-version: 9.6.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

push-sender/build.gradle

@@ -11,6 +11,6 @@ repositories {
 
 dependencies {
     implementation 'org.jetbrains.kotlin:kotlin-stdlib'
-    implementation 'com.google.firebase:firebase-admin:9.5.0'
+    implementation 'com.google.firebase:firebase-admin:9.6.0'
     implementation 'org.slf4j:slf4j-simple:2.0.17'
 }