Don't publish test

The test vectors are pretty big, let's not put them in the crate.

Cargo.toml

@@ -1,13 +1,14 @@
 [package]
 name = "hpke-rs"
-version = "0.2.0"
+version = "0.2.1-pre.1"
 authors = ["Franziskus Kiefer <[email protected]>"]
 edition = "2021"
 license = "MPL-2.0"
 documentation = "https://docs.rs/hpke-rs"
 description = "HPKE Implementation"
 readme = "Readme.md"
 repository = "https://github.com/franziskuskiefer/hpke-rs"
+exclude = ["/tests"]
 
 [dependencies]
 log = "0.4"