all: release v1.36.4

Change-Id: I0982b0714f2f250df0db242d6300cb5f44d999bf
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/643956
Reviewed-by: Chressie Himpel <chressie@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

internal/version/version.go

diff --git a/internal/version/version.go b/internal/version/version.go
index 9110034..4a39af0 100644
--- a/internal/version/version.go
+++ b/internal/version/version.go
@@ -52,8 +52,8 @@
 const (
 	Major      = 1
 	Minor      = 36
-	Patch      = 3
-	PreRelease = "devel"
+	Patch      = 4
+	PreRelease = ""
 )
 
 // String formats the version string for this module in semver format.