Update release.rst

Remove old releases
diff --git a/doc/source/release.rst b/doc/source/release.rst
index 74e4fe4..da32a73 100644
--- a/doc/source/release.rst
+++ b/doc/source/release.rst
@@ -417,7 +417,7 @@
    mkdir ${RELEASE_VERSION}-incubating
    cd ${RELEASE_VERSION}-incubating
    # copy the tar.gz. asc. and sha512 files for the src and binary releases
-
+   # Remove old releases and commit
 
 3. Release nexus artifacts. Follow the step 12 in the release process but this time press the ``release`` button.