Fix docker build OOMing in CI for arm64 builds (#14173)

Co-authored-by: David Robertson <davidr@element.io>

.github/workflows/docker.yml

@@ -27,7 +27,7 @@ jobs:
 
       - name: Inspect builder
         run: docker buildx inspect
-          
+
       - name: Log in to DockerHub
         uses: docker/login-action@v2
         with:
@@ -55,3 +55,6 @@ jobs:
           tags: "${{ steps.set-tag.outputs.tags }}"
           file: "docker/Dockerfile"
           platforms: linux/amd64,linux/arm64
+          build-args:
+            # arm64 builds OOM otherwise. c.f. https://github.com/rust-lang/cargo/issues/10583
+            CARGO_NET_GIT_FETCH_WITH_CLI: true