deps: update dependency com.google.cloud:google-cloud-shared-dependencies to v3.21.0 (#1518)

Author: renovate-bot

pom.xml

@@ -181,7 +181,7 @@
       <dependency>
         <groupId>com.google.cloud</groupId>
         <artifactId>google-cloud-shared-dependencies</artifactId>
-        <version>3.20.0</version>
+        <version>3.21.0</version>
         <type>pom</type>
         <scope>import</scope>
       </dependency>