Fix git clean command

jasongrout · web-flow · commit 65fc04df034d · 2020-09-29T18:26:22.000-07:00
diff --git a/RELEASE.md b/RELEASE.md
@@ -1,7 +1,7 @@
 To create a release, update the version number in jupyter_server/_version.py, then run the following:
 
 ```
-git clean -dfxx
+git clean -dffx
 python setup.py sdist
 python setup.py bdist_wheel
 export script_version=`python setup.py --version 2>/dev/null`
