Revert accidental changes

Author: yuxiqian

flink-cdc-common/pom.xml

@@ -41,14 +41,6 @@ limitations under the License.
                     </execution>
                 </executions>
             </plugin>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-compiler-plugin</artifactId>
-                <configuration>
-                    <source>8</source>
-                    <target>8</target>
-                </configuration>
-            </plugin>
         </plugins>
     </build>