Merge pull request #476 from SciML/downgrade-toplevel-to-5.21.0

Set top-level version to 5.21.0 for sequential registration

Author: ChrisRackauckas

Project.toml

@@ -1,6 +1,6 @@
 name = "BoundaryValueDiffEq"
 uuid = "764a87c0-6b3e-53db-9096-fe964310641d"
-version = "5.22.0"
+version = "5.21.0"
 
 [deps]
 ADTypes = "47edcb42-4c32-4615-8424-f2b9edc5f35b"