Fix(CI): Use canonical name for arm64

While docker accepts `linux/arm64/v8` as an alias for `linux/arm64`, it
still uses `linux/arm64` for it's $TARGETPLATFORM build arg.
As a result, the correct binary could not be copied into the CI's docker
image.

.gitlab-ci.yml

@@ -142,7 +142,7 @@ build:debug:cargo:x86_64-unknown-linux-musl:
     DOCKER_HOST: tcp://docker:2375/
     DOCKER_TLS_CERTDIR: ""
     DOCKER_DRIVER: overlay2
-    PLATFORMS: "linux/arm/v6,linux/arm/v7,linux/arm64/v8,linux/amd64"
+    PLATFORMS: "linux/arm/v6,linux/arm/v7,linux/arm64,linux/amd64"
     DOCKER_FILE: "docker/ci-binaries-packaging.Dockerfile"
   before_script:
     - docker login -u "$CI_REGISTRY_USER" -p "$CI_REGISTRY_PASSWORD" $CI_REGISTRY
@@ -156,7 +156,7 @@ build:debug:cargo:x86_64-unknown-linux-musl:
     - mkdir -p linux/ && mv ./conduit-x86_64-unknown-linux-musl linux/amd64
     - mkdir -p linux/arm/ && mv ./conduit-arm-unknown-linux-musleabihf linux/arm/v6
     - mkdir -p linux/arm/ && mv ./conduit-armv7-unknown-linux-musleabihf linux/arm/v7
-    - mkdir -p linux/arm64/ && mv ./conduit-aarch64-unknown-linux-musl linux/arm64/v8
+    - mv ./conduit-aarch64-unknown-linux-musl linux/arm64
     # Actually create multiarch image:
     - >
       docker buildx build