Fix did:plc

src/did.rs

···
 }
 
 fn get_plc_doc(plc: &str) -> Result<DidDoc, ()> {
-    let res = match reqwest::blocking::get("https://plc.directory/did:plc".to_owned() + plc) {
+    let res = match reqwest::blocking::get("https://plc.directory/did:plc:".to_owned() + plc) {
         Ok(val) => val,
         Err(_) => return Err(()),
     };