chore(logging): make environment test script executable (#3855)
chore(logging): make environment test script executable (#3855)

This fixes the issue: 

Executing: docker run --rm --interactive --network=host --privileged --volume=/var/run/docker.sock:/var/run/docker.sock --workdir=/tmpfs/src --entrypoint=github/google-cloud-go/internal/kokoro/environment.sh --env-file=/tmpfs/tmp/tmpq4cc73na/envfile --volume=/tmpfs:/tmpfs gcr.io/cloud-devrel-kokoro-resources/go116
docker: Error response from daemon: OCI runtime create failed: container_linux.go:344: starting container process caused "exec: \"github/google-cloud-go/internal/kokoro/environment.sh\": permission denied": unknown.
googleapis/google-cloud-go,googleapis/google-cloud-go,googleapis/google-cloud-go,googleapis/google-cloud-go