Bump to 0.5.0. (#51)

diff --git a/Cargo.toml b/Cargo.toml
index d1e5db2..4604fce 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -24,7 +24,7 @@
 
 [package]
 name = "skywalking"
-version = "0.4.0"
+version = "0.5.0"
 authors = ["Apache Software Foundation"]
 edition = "2021"
 description = "Apache SkyWalking Rust Agent"