cli: mark the tree 0.2.0-rc1

The release-candidate version lands in 'pkh --version' and in the
build records' manifests, so an RC-tested tree is distinguishable
from the final release.

Cargo.lock

@@ -1496,7 +1496,7 @@ checksum = "f6b464fbc74e149a392436b17d523f769e057cb6877f6a5c4618bc6f11800548"
 
 [[package]]
 name = "pkh"
-version = "0.2.0"
+version = "0.2.0-rc1"
 dependencies = [
  "bzip2-rs",
  "chrono",

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "pkh"
-version = "0.2.0"
+version = "0.2.0-rc1"
 edition = "2024"
 authors = ["vhaudiquet"]
 description = "pkh is a packaging helper for Debian/Ubuntu packages"