deps: Downgrade oci-client to 0.15

In oci-client 0.16.0, parse_expiration_from_jwt uses
jsonwebtoken::dangerous::insecure_decode to parse the bearer token.
Registries like GHCR.io issue opaque tokens (not JWTs), so this decode
fails, returning early and not caching the token. The kwctl pull suceeds
because the token is used directly in the HTTP requests, but without the
cache, each request will fetch a fresh token, and this will happen for
each layer pull, which amounts to a performance penalty.

This needs to be fixed upstream, but meanwhile, we can downgrade
oci-client to 0.15 in policy-fetcher.

Signed-off-by: Víctor Cuadrado Juan <vcuadradojuan@suse.de>

Author: viccuad

Cargo.lock

@@ -20,7 +20,7 @@ directories = "6.0"
 docker_credential = "1.3"
 futures = { workspace = true }
 lazy_static = { workspace = true }
-oci-client = { version = "0.16", default-features = false, features = [
+oci-client = { version = "0.15", default-features = false, features = [
   "rustls-tls",
 ] }
 path-slash = "0.2"