Add git tags from last deployment to environment detail page

...assets/javascripts/environments/components/deployment.vue

...ascripts/environments/components/new_environment_item.vue

...ronments/graphql/queries/deployment_details.query.graphql

app/graphql/types/deployment_details_type.rb

app/graphql/types/deployment_tag_type.rb

app/models/deployment.rb

app/models/repository.rb

app/presenters/deployments/deployment_presenter.rb

doc/api/graphql/reference/index.md

ee/spec/frontend/environments/new_environment_item_spec.js

lib/gitlab/git/repository.rb

spec/frontend/environments/deployment_spec.js

spec/frontend/environments/environments_app_spec.js

spec/frontend/environments/graphql/mock_data.js

spec/frontend/environments/new_environment_item_spec.js

spec/graphql/types/deployment_details_type_spec.rb

spec/graphql/types/detployment_tag_type_spec.rb

spec/models/deployment_spec.rb

spec/presenters/deployments/deployment_presenter_spec.rb