Update CONTRIBUTING.md

CONTRIBUTING.md

@@ -9,8 +9,10 @@ Please include:
 - your environment (stand alone or distributed)
 - the OS of your CMK server(s)
 - the version of the plugin
+- the version of the inventory plugin(s)
 - the crash report (if any)
 - the output of the nvdct (including the complete command line)
 - the coniguration file of nvdct (by default nvdct.toml)
+- the nvdct log file (in some cases with the `--log-level DEBUG` option)
 
-For issues with the inventory plugins see the contribution guide lines of the inventory plugin.
\ No newline at end of file
+For issues with the inventory plugins see the contribution guide lines of the inventory plugin.