deps: update dependency org.springframework.boot:spring-boot-starter-test to v2.6.6 (#756)

* deps: update dependency org.springframework.boot:spring-boot-starter-test to v2.6.6 * 🦉 Updates from OwlBot post-processor See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

Author: renovate-bot

samples/snippets/cloud-client/src/pom.xml

@@ -105,7 +105,7 @@
  <dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-test</artifactId>
- <version>2.6.5</version>
+ <version>2.6.6</version>
  <scope>test</scope>
  </dependency>
  <dependency>