all: start v1.22.0-devel

Change-Id: I7d70cbd4c9b692b5e4ffdfc576458c48d39f450d
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/232118
Reviewed-by: Damien Neil <dneil@google.com>
diff --git a/internal/version/version.go b/internal/version/version.go
index 774719e..ca4aebb 100644
--- a/internal/version/version.go
+++ b/internal/version/version.go
@@ -54,7 +54,7 @@
 	Major      = 1
 	Minor      = 22
 	Patch      = 0
-	PreRelease = ""
+	PreRelease = "devel"
 )
 
 // String formats the version string for this module in semver format.