Add back peer_dn field to Port on pg17.. (pgcentralfoundation#2200)

Catch the field I accidentally dropped while splitting `Port` into
different written-out versions, thanks to @cbandy!

Author: workingjubilee

pgrx-pg-sys/src/libpq.rs

@@ -112,6 +112,7 @@ pub mod be {
 
         ssl_in_use: bool,
         peer_cn: *mut core::ffi::c_char,
+        peer_dn: *mut core::ffi::c_char,
         peer_cert_valid: bool,
 
         alpn_used: bool,
@@ -186,6 +187,7 @@ pub mod be {
 
         ssl_in_use: bool,
         peer_cn: *mut core::ffi::c_char,
+        peer_dn: *mut core::ffi::c_char,
         peer_cert_valid: bool,
 
         alpn_used: bool,