Revert "Release candidate changes"

This reverts commits:
  951d12c6ab3bc8221ae252f0d6948084d51af7b8
  b4b95a644277fd88eb93fceb6d811ee4bbd8fb56
  4f2c3fc616acfa33a01a60338f8c7396586ceead
due to the failure of RCO.
diff --git a/.auroraversion b/.auroraversion
index 4d67773..b380fee 100644
--- a/.auroraversion
+++ b/.auroraversion
@@ -1 +1 @@
-0.23.0-SNAPSHOT
+0.22.0-SNAPSHOT
diff --git a/CHANGELOG b/CHANGELOG
index 4c3608c..8dd9ee9 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,6 +1,3 @@
-Aurora 0.22.0
---------------------------------------------------------------------------------
-
 Aurora 0.21.0
 --------------------------------------------------------------------------------
 
diff --git a/RELEASE-NOTES.md b/RELEASE-NOTES.md
index 21eacac..5ad6f85 100644
--- a/RELEASE-NOTES.md
+++ b/RELEASE-NOTES.md
@@ -1,4 +1,4 @@
-0.22.0
+0.22.0 (unreleased)
 ======
 
 ### New/updated: