all: start v1.36.0-devel

Change-Id: Id47a99eafd700576f84f31f5f1b585c7aef8b0b4
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/636676
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Chressie Himpel <chressie@google.com>

internal/version/version.go

@@ -53,7 +53,7 @@ const (
 	Major      = 1
 	Minor      = 36
 	Patch      = 0
-	PreRelease = ""
+	PreRelease = "devel"
 )
 
 // String formats the version string for this module in semver format.