build(deps): update dependency org.apache.maven.plugins:maven-gpg-plugin to v3.2.8

Author: renovate-bot

google-cloud-bom/pom.xml

@@ -368,7 +368,7 @@
  <plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-gpg-plugin</artifactId>
- <version>3.2.7</version>
+ <version>3.2.8</version>
  <executions>
  <execution>
  <id>sign-artifacts</id>

libraries-bom/pom.xml

@@ -154,7 +154,7 @@
  <plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-gpg-plugin</artifactId>
- <version>3.2.7</version>
+ <version>3.2.8</version>
  <executions>
  <execution>
  <id>sign-artifacts</id>