Check package name org.apache.skywalking (#3581)

* Check package name org.apache.skywalking

* Only check REAL sources

apm-checkstyle/checkStyle.xml

@@ -82,7 +82,9 @@
         <module name="MethodTypeParameterName">
             <property name="format" value="(^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$)"/>
         </module>
-        <module name="PackageName"/>
+        <module name="PackageName">
+            <property name="format" value="^org\.apache\.skywalking(\.[a-zA-Z][a-zA-Z0-9]*)+$"/>
+        </module>
         <module name="ParameterName"/>
         <module name="StaticVariableName">
             <property name="format" value="(^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$)"/>

pom.xml

@@ -492,7 +492,10 @@
                     <consoleOutput>true</consoleOutput>
                     <includeTestSourceDirectory>true</includeTestSourceDirectory>
                     <failsOnError>true</failsOnError>
-                    <includes>org/apache/skywalking/**/*.java</includes>
+                    <sourceDirectories>
+                        <sourceDirectory>${project.build.sourceDirectory}</sourceDirectory>
+                        <sourceDirectory>${project.build.testSourceDirectory}</sourceDirectory>
+                    </sourceDirectories>
                     <resourceIncludes>
                         **/*.properties,
                         **/*.sh,