chore: remove docker credentials for PRs

Author: JenniferMah

.travis.yml

@@ -7,7 +7,9 @@ mono: none
 services:
 - docker
 script:
-- echo "$DOCKER_PASSWORD" | docker login -u "$DOCKER_USERNAME" --password-stdin
+- if [[ "$TRAVIS_BRANCH" == "main"  ||  "$TRAVIS_BRANCH" == "travis" ]] && [ "$TRAVIS_PULL_REQUEST" == "false" ]; then
+  echo "${DOCKER_PASSWORD}" | docker login -u "${DOCKER_USERNAME}" --password-stdin;
+  fi
 - make test-docker
 - make release
 after_success: