Chore: bump version to v0.2.18

Signed-off-by: Nico Burns <nico@nicoburns.com>

Author: nicoburns

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "thin-vec"
-version = "0.2.17"
+version = "0.2.18"
 authors = ["Aria Beingessner <a.beingessner@gmail.com>"]
 edition = "2018"
 rust-version = "1.53"