chore(deps): do not upgrade pulldown-cmark

The `pulldown-cmark-mdcat` is using the previous version of `pulldown-cmark`.

Unfortunately `pulldown-cmark-mdcat` is part of `mdcat`, which has been archived by the maintainer last month (Jan 2025).

We have to understand how we can move forward. In the meantime we cannot
update this dependency.

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

Author: flavio

Cargo.toml

@@ -25,7 +25,7 @@ pulldown-cmark-mdcat = { version = "2.7.1", default-features = false }
 policy-evaluator = { git = "https://github.com/kubewarden/policy-evaluator", tag = "v0.19.11" }
 rustls-pki-types = { version = "1", features = ["alloc"] }
 prettytable-rs = "^0.10"
-pulldown-cmark = { version = "0.13.0", default-features = false }
+pulldown-cmark = { version = "0.12", default-features = false }
 regex = "1"
 serde_json = "1.0"
 serde = { version = "1.0", features = ["derive"] }