linux.yml in fluent-plugin-kafka-0.17.1

- old
+ new

@@ -3,9 +3,11 @@
   - push
   - pull_request
 jobs:
   build:
     runs-on: ${{ matrix.os }}
+    env:
+      USE_RDKAFKA: 1
     strategy:
       fail-fast: false
       matrix:
         ruby: [ '2.4', '2.5', '2.6', '2.7', '3.0' ]
         os: