Change version to 1.24.1-dev (#3042)

diff --git a/version.go b/version.go
index 483ef89..d0c0a73 100644
--- a/version.go
+++ b/version.go
@@ -19,4 +19,4 @@
 package grpc
 
 // Version is the current grpc version.
-const Version = "1.24.0"
+const Version = "1.24.1-dev"