Release 2.0.6 (#3900)

* cleanup invoice templates
* cleanup invoice translations
* fix invoice datetime for now
* support invoice archive order by number and status
* bump version
* allow meta-field sub-classing
* removed unused translation task.delete
* prevent null in str_replace

translations/invoice-renderer.zh_CN.xlf

@@ -18,10 +18,6 @@
         <source>service-date</source>
         <target>兼职人员</target>
       </trans-unit>
-      <trans-unit id="nA.KOyM" resname="Html">
-        <source>Html</source>
-        <target state="translated">HTML（用于通过浏览器打印）</target>
-      </trans-unit>
       <trans-unit id="N6juwc4" resname="default">
         <source>default</source>
         <target state="translated">发票</target>