Run `mirror update` on CI even if tests failed

If a commit introduced a new Ruby definition, we want it mirrored even
if there might have been an accidental failure on CI.

script/test

@@ -3,8 +3,11 @@ set -e
 
 [ -d ./bats/bin ] && export PATH=./bats/bin:"$PATH"
 
-bats -t test
+STATUS=0
+bats -t test || STATUS="$?"
 
 if [ "$TRAVIS_SECURE_ENV_VARS" = "true" ]; then
   ./script/mirror update "$TRAVIS_COMMIT_RANGE"
 fi
+
+exit "$STATUS"