fix(ci): Fix musl builds

This pins the image to use for cross to a working image's sha256

.gitlab-ci.yml

@@ -26,7 +26,7 @@ variables:
     - if: "$CI_COMMIT_TAG"
     - if: '($CI_MERGE_REQUEST_APPROVED == "true") || $BUILD_EVERYTHING' # Once MR is approved, test all builds. Or if BUILD_EVERYTHING is set.
   interruptible: true
-  image: "registry.gitlab.com/jfowl/conduit-containers/rust-with-tools:latest"
+  image: "registry.gitlab.com/jfowl/conduit-containers/rust-with-tools@sha256:69ab327974aef4cc0daf4273579253bf7ae5e379a6c52729b83137e4caa9d093"
   tags: ["docker"]
   services: ["docker:dind"]
   variables:

Cross.toml

@@ -20,4 +20,4 @@ image = "registry.gitlab.com/jfowl/conduit-containers/rust-cross-arm-unknown-lin
 image = "registry.gitlab.com/jfowl/conduit-containers/rust-cross-armv7-unknown-linux-musleabihf:latest"
 
 [target.x86_64-unknown-linux-musl]
-image = "registry.gitlab.com/jfowl/conduit-containers/rust-cross-x86_64-unknown-linux-musl:latest"
+image = "registry.gitlab.com/jfowl/conduit-containers/rust-cross-x86_64-unknown-linux-musl@sha256:b6d689e42f0236c8a38b961bca2a12086018b85ed20e0826310421daf182e2bb"