circle-ci can't build rust projects on their free tier

.circleci/config.yml

@@ -1,24 +0,0 @@
-version: 2
-jobs:
-    build:
-        docker:
-            - image: circleci/rust:latest
-        steps:
-            - checkout
-            - restore_cache:
-                key: project-cache
-            - run:
-                name: Stable Build
-                command: |
-                    cargo --version --verbose
-                    cargo build -j 1
-            - run:
-                name: Stable Test (lib)
-                command: cargo test -j 1 --lib
-            - run:
-                name: Stable Test (doc)
-                command: cargo test -j 1 --doc
-            - save_cache:
-                key: project-cache
-                paths:
-                    - "~/.cargo"