book: Remove unused dirs dependency

Author: daxhuiberts

book/listings/Cargo.lock

@@ -9,7 +9,6 @@ adw = { version = "0.7", package = "libadwaita", features = ["v1_5"] }
 anyhow = "1.0"
 ashpd = { version = "0.9", features = ["gtk4"] }
 async-channel = "2.0"
-dirs = "5.0"
 gtk = { version = "0.9", package = "gtk4", features = ["v4_12"] }
 reqwest = { version = "0.12", default-features = false, features = [
     "rustls-tls",