Merge pull request #193 from paritytech/CI_optimizations

CI optimizations

.gitlab-ci.yml

@@ -7,6 +7,8 @@ image:                             parity/rust-builder:latest
 variables:
   GIT_STRATEGY:                    fetch
   GIT_SUBMODULE_STRATEGY:          recursive
+  GIT_DEPTH:                       3
+  CARGO_INCREMENTAL:               0
   CARGO_HOME:                      "/ci-cache/${CI_PROJECT_NAME}/cargo/${CI_JOB_NAME}"
   SCCACHE_DIR:                     "/ci-cache/${CI_PROJECT_NAME}/sccache"
   CI_SERVER_NAME:                  "GitLab CI"
@@ -15,12 +17,16 @@ variables:
 .docker-env:                       &docker-env
   image:                           parity/rust-builder:latest
   before_script:
+    - cargo -vV
+    - rustc -vV
     - rustup show
     - cargo --version
     - sccache -s
+  dependencies:                    []
+  interruptible:                   true
   retry:
     max: 2
-    when: 
+    when:
       - runner_system_failure
       - unknown_failure
       - api_failure