ci: Don't run cargo update as part of the CI

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer-rs/-/merge_requests/1334>

.gitlab-ci.yml

@@ -95,13 +95,6 @@ trigger:
   before_script:
     - source ./ci/env.sh
     - mkdir .cargo && echo -e "[net]\ngit-fetch-with-cli = true" > .cargo/config
-    # If cargo exists assume we probably will want to update
-    # the lockfile
-    - |
-      if command -v cargo; then
-        cargo generate-lockfile --color=always
-        cargo update --color=always
-      fi
 
 .debian:12-base:
   extends: .debian:12