if travis tag is set then create debian package

.travis.yml

@@ -26,7 +26,7 @@ script:
   - go build -o $DELIVERABLE
   - $SHA512_CMD $DELIVERABLE > ${DELIVERABLE}.sha512.txt
   - if [ "$TRAVIS_OS_NAME" == "linux" ] && [ "$TRAVIS_PULL_REQUEST" == "false" ]; then sonar-scanner -Dsonar.projectKey=030_go-yq -Dsonar.sources=. -Dsonar.host.url=https://sonarcloud.io -Dsonar.coverage.exclusions=**/*_test.go -Dsonar.go.coverage.reportPaths="coverage.out"; fi
-  - if [ "$TRAVIS_OS_NAME" == "linux" ]; then cp $DELIVERABLE go-yq && a2deb -app go-yq -version ${TRAVIS_TAG} -maintainer "030 <[email protected]>" -description "jq-style golang equivalent of yq"; fi
+  - if [ "$TRAVIS_OS_NAME" == "linux" ] && [ -n "${TRAVIS_TAG}" ]; then cp $DELIVERABLE go-yq && a2deb -app go-yq -version ${TRAVIS_TAG} -maintainer "030 <[email protected]>" -description "jq-style golang equivalent of yq"; fi
 deploy:
   provider: releases
   api_key: $GITHUB_TOKEN