chore: update rPGP from 0.20.0 to 0.21.0

Main updates are security fix (fixed panic on short session keys)
and stabilized PQC (feature renamed from "draft-pqc" to "pqc").

Cargo.lock

@@ -4246,9 +4246,9 @@ dependencies = [
 
 [[package]]
 name = "pgp"
-version = "0.20.0"
+version = "0.21.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1cfa4743b28656065ff4c0ba09e46b357a65e8c00fc2341e89084b82f87cbdf1"
+checksum = "ae70f4d9325a391db30d115d6191a7bb67cec856aa0bba131290f0c4e09a532a"
 dependencies = [
  "aead",
  "aes",

Cargo.toml

@@ -77,7 +77,7 @@ num-derive = "0.4"
 num-traits = { workspace = true }
 parking_lot = "0.12.4"
 percent-encoding = "2.3"
-pgp = { version = "0.20.0", features = ["draft-pqc"], default-features = false }
+pgp = { version = "0.21.0", features = ["pqc"], default-features = false }
 pin-project = "1"
 qrcodegen = "1.7.0"
 quick-xml = { version = "0.41", features = ["escape-html"] }