Set env var w/ env syntax

Author: ultraq

.github/workflows/benchmark.yml

@@ -14,6 +14,7 @@ jobs:
       - name: Install JMeter
         run: |
           curl https://dlcdn.apache.org//jmeter/binaries/apache-jmeter-5.6.3.tgz --output /tmp/apache-jmeter-5.6.3.tgz
-          tar -xf /tmp/apache-jmeter-5.6.3.tgz
-          export JMETER_HOME=/tmp/apache-jmeter-5.6.3
+          tar -xvf /tmp/apache-jmeter-5.6.3.tgz
       - run: ./gradlew benchmark
+        env:
+          JMETER_HOME: /tmp/apache-jmeter-5.6.3