switching from a full build to 'cargo check' in CI

accomplishes mostly the same thing for my purposes and reduces
the CI run time.

.build.yml

@@ -9,5 +9,5 @@ environment:
 tasks:
   - build: |
       cd clinte
-      cargo test
-      cargo build
+      cargo check
+      cargo test

.travis.yml

@@ -15,6 +15,6 @@ before_script:
     - bash <(curl https://raw.githubusercontent.com/xd009642/tarpaulin/master/travis-install.sh)
 
 script:
-    - cargo build --verbose
+    - cargo check
     - cargo tarpaulin --out Xml
     - bash <(curl -s https://codecov.io/bash)