fix(deps): bump quinn-udp to 0.5.16 (RUSTSEC-2026-0538)

quinn-udp 0.5.14 has a receive loop that can spin after a truncated datagram.
The advisory names >=0.5.16 as the fix. It is reached only through
libp2p-quic. Lockfile-only change; cargo audit exits 0 with it and reports the
advisory without it.

Cargo.lock

@@ -2208,7 +2208,7 @@ version = "3.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "faf9468729b8cbcea668e36183cb69d317348c2e08e994829fb56ebfdfbaac34"
 dependencies = [
- "windows-sys 0.61.2",
+ "windows-sys 0.48.0",
 ]
 
 [[package]]
@@ -2701,7 +2701,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7ab67060fc6b8ef687992d439ca0fa36e7ed17e9a0b16b25b601e8757df720de"
 dependencies = [
  "data-encoding",
- "syn 2.0.117",
+ "syn 1.0.109",
 ]
 
 [[package]]
@@ -5779,16 +5779,16 @@ dependencies = [
 
 [[package]]
 name = "quinn-udp"
-version = "0.5.14"
+version = "0.5.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "addec6a0dcad8a8d96a771f815f0eaf55f9d1805756410b39f5fa81332574cbd"
+checksum = "af66907df18639dcf4db56ca65490cabc4b27a97dbadd96f2926cca73298f016"
 dependencies = [
  "cfg_aliases",
  "libc",
  "once_cell",
  "socket2",
  "tracing",
- "windows-sys 0.52.0",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -7959,7 +7959,7 @@ version = "0.1.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c2a7b1c03c876122aa43f3020e6c3c3ee5c05081c9a00739faf7503aeba10d22"
 dependencies = [
- "windows-sys 0.61.2",
+ "windows-sys 0.48.0",
 ]
 
 [[package]]