fix: address failure when parsing policies.yml file

There seeems to be issues with the usage of the `deny_unknown_fields`
and untagged enumerations.
serde ends up confused and complains about perfectly valid files.

See serde-rs/serde#1600

Signed-off-by: Flavio Castelli <fcastelli@suse.com>

Author: flavio

src/config.rs

@@ -333,7 +333,7 @@ impl PolicyGroupMember {
 
 /// Describes a policy that can be either an individual policy or a group policy.
 #[derive(Deserialize, Debug, Clone)]
-#[serde(deny_unknown_fields, untagged, rename_all = "camelCase")]
+#[serde(untagged, rename_all = "camelCase")]
 pub enum PolicyOrPolicyGroup {
     /// An individual policy
     Policy {