make config PathBuf instead of String

Signed-off-by: strawberry <strawberry@puppygock.gay>

src/clap.rs

 //! Integration with `clap`
 
+use std::path::PathBuf;
+
 use clap::Parser;
 
 /// Commandline arguments
@@ -8,7 +10,7 @@
 pub struct Args {
 	#[arg(short, long)]
 	/// Optional argument to the path of a conduwuit config TOML file
-	pub config: Option<String>,
+	pub config: Option<PathBuf>,
 }
 
 /// Parse commandline arguments into structured data