openpgp: Update rust-crypto dependencies

  - Note: `x25519-dalek` is broken.  It depends on zeroize `=1.3`, but
    crates like rsa depend on newer versions of zeroize.

  - See WebAssembly/wasi-crypto#63 ,
    dalek-cryptography/x25519-dalek#92 .

  - Resolve this by using `x25519-dalek-ng`, which fixes this issue.
    This is a common workaround, and is also used by, for instance
    OpenMLS:

    https://github.com/openmls/openmls/blob/3ff090fd4881cb796d4688f7f174929a7521dbf1/openmls_rust_crypto/README.md?plain=1#L3

  - Fixes #910.

.gitlab-ci.yml

@@ -61,12 +61,18 @@ bookworm:
     CARGO_TARGET_DIR: /target
     CARGO_HOME: /cargo
 
-bookworm-crypto-rust:
+# XXX: Our MSRV is 1.63 except with rust-crypto, which requires
+# 1.65.  Switch back to bookworm, when rustc is >= 1.65.
+#
+# bookworm-crypto-rust:
+#   image: 192.168.122.1:5000/sequoia-pgp/build-docker-image/bookworm-prebuild:latest
+rust-stable-crypto-rust:
   tags:
     - linux
   stage: build
   interruptible: true
-  image: 192.168.122.1:5000/sequoia-pgp/build-docker-image/bookworm-prebuild:latest
+
+  image: 192.168.122.1:5000/sequoia-pgp/build-docker-image/rust-stable-prebuild:latest
   dependencies:
     - codespell
   script: