ci: excluding jackson from upper-bound-check

Excluding Jackson from the upper-bound-check because it's not part
of the artifacts we provide to customers.

upper-bound-check/pom.xml

@@ -259,4 +259,31 @@
       <artifactId>grpc-google-iam-v1</artifactId>
     </dependency>
   </dependencies>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-enforcer-plugin</artifactId>
+        <executions>
+          <execution>
+            <id>enforce</id>
+            <goals>
+              <goal>enforce</goal>
+            </goals>
+            <configuration>
+              <rules>
+                <requireUpperBoundDeps>
+                  <excludes>
+                    <!-- Jackson is not part of the artifacts we provide to customers -->
+                    <exclude>com.fasterxml.jackson.core:jackson-core</exclude>
+                  </excludes>
+                </requireUpperBoundDeps>
+              </rules>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
 </project>