Update Rust crate pulldown-cmark to 0.12.0

Author: renovate[bot]

Cargo.toml

@@ -15,7 +15,7 @@ edition = "2021"
 mdbook = "^0.4.37"
 clap = { version = "4.5.4", features = ["derive"] }
 serde_json = "1.0.116"
-pulldown-cmark = "0.10.3"
+pulldown-cmark = "0.12.0"
 pulldown-cmark-to-cmark = "13.0"
 
 lazy_static = "1.4.0"