[pom] Fix xml

Author: hazendaz

mybatis-scala-core/pom.xml

@@ -70,12 +70,14 @@
       <plugin>
         <groupId>net.alchim31.maven</groupId>
         <artifactId>scala-maven-plugin</artifactId>
-        <execution>
-          <id>attach-javadocs</id>
-          <goals>
-            <goal>doc-jar</goal>
-          </goals>
-        </execution>
+        <executions>
+          <execution>
+            <id>attach-javadocs</id>
+            <goals>
+              <goal>doc-jar</goal>
+            </goals>
+          </execution>
+        </executions>
       </plugin>
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>