feat: add mockito dependency (#284)

* feat: add mockito dependency

* feat: add mockito dependency

Author: dmitry-fa

google-cloud-storage/pom.xml

@@ -156,6 +156,11 @@
       <artifactId>easymock</artifactId>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>org.mockito</groupId>
+      <artifactId>mockito-core</artifactId>
+      <scope>test</scope>
+    </dependency>
     <dependency>
       <groupId>org.objenesis</groupId>
       <artifactId>objenesis</artifactId>