Cargo.*: increment version to 0.13.0

Author: lpenz

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "rustsourcebundler"
-version = "0.12.0"
+version = "0.13.0"
 authors = ["Leandro Lisboa Penz <lpenz@lpenz.org>"]
 description = "Bundle the source code of a rust cargo crate in a single source file"
 license = "MIT"