Pass RUST_BACKTRACE when running docker.

Author: jfgoog

src/ci/docker/run.sh

@@ -323,6 +323,7 @@ docker \
   --env GITHUB_ACTIONS \
   --env GITHUB_REF \
   --env GITHUB_STEP_SUMMARY="/checkout/obj/${SUMMARY_FILE}" \
+  --env RUST_BACKTRACE \
   --env TOOLSTATE_REPO_ACCESS_TOKEN \
   --env TOOLSTATE_REPO \
   --env TOOLSTATE_PUBLISH \