Add pom exclude license file dir. (#4217)

* add exclude licene file dir.

* update comment.

* update pom exclude dir.

* update comment.
Co-authored-by: Nkezhenxu94 <kezhenxu94@163.com>
Co-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>

pom.xml

@@ -452,6 +452,9 @@
                         <exclude>tools/dependencies/known-oap-backend-dependencies.txt</exclude>
                         <exclude>apm-checkstyle/CHECKSTYLE_HEAD</exclude>
 
+                        <!-- generated file from test agent plugin scenarios -->
+                        <exclude>**/test/plugin/workspace/**</exclude>
+
                         <exclude>.m2/**</exclude>
                     </excludes>
                 </configuration>