Bump rust from 1.67-bullseye to 1.94-bullseye

Bumps rust from 1.67-bullseye to 1.94-bullseye.

---
updated-dependencies:
- dependency-name: rust
  dependency-version: 1.94-bullseye
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

tester-k.dockerfile

@@ -2,7 +2,7 @@
 
 ARG mina_daemon_image
 
-FROM rust:1.67-bullseye as builder
+FROM rust:1.94-bullseye as builder
 
 RUN curl -sSL https://capnproto.org/capnproto-c++-0.10.2.tar.gz | tar -zxf - \
   && cd capnproto-c++-0.10.2 \