ci: add RUST_BACKTRACE=1 for unit test

Useful for debugging unit test failures.

Signed-off-by: wanglei01 <[email protected]>

Author: wllenyj

.github/workflows/rust.yml

@@ -15,6 +15,8 @@ jobs:
     steps:
     - uses: actions/checkout@v2
     - name: build and check
+      env:
+        RUST_BACKTRACE: 1
       run: make check
     - name: smoke
       run: make docker-smoke