landlock: Bump to 0.2.0

Release a new crate version for current users before bringing more
invasive API breaking changes (see landlock-lsm#12 and landlock-lsm#23).  The API is not ready
to be stable yet but perfect is the enemy of good.

Switch to the 2021 Rust edition.

Only keep myself as the current maintainer.  Thanks Vincent for the
collaboration in early development!

Signed-off-by: Mickaël Salaün <mic@digikod.net>

Cargo.toml

@@ -1,12 +1,9 @@
 [package]
 name = "landlock"
-version = "0.1.0"
-authors = [
-	"Mickaël Salaün <mic@digikod.net>",
-	"Vincent Dagonneau <vincentdagonneau@gmail.com>"
-]
-edition = "2018"
+version = "0.2.0"
+edition = "2021"
 rust-version = "1.63"
+authors = ["Mickaël Salaün <mic@digikod.net>"]
 description = "Landlock LSM helpers"
 homepage = "https://landlock.io"
 repository = "https://github.com/landlock-lsm/rust-landlock"