Add a `version` command

[ledouxpl]

Adding a version command printing out the pubsub_cli version would be neat.

Without this feature, knowing which version is installed in our containers is difficult.

[k-yomo]

You can check the version with pubsub_cli -v!

[ledouxpl]

🤔 It does not seem to work on my end, at least with version 1.7.1...

root@2b6fe3149e85:~# pubsub_cli -v
Error: unknown shorthand flag: 'v' in -v
Usage:
  pubsub_cli [command]

Available Commands:
  completion          generate the autocompletion script for the specified shell
  connect             connect remote topics to local topics
  create_subscription create Pub/Sub subscription
  create_topic        create Pub/Sub topic
  help                Help about any command
  publish             publish Pub/Sub message
  register_push       register Pub/Sub push endpoint
  subscribe           subscribe Pub/Sub topics

Flags:
  -c, --cred-file string   gcp credential file path (You can also set 'GOOGLE_APPLICATION_CREDENTIALS' to env variable)
      --help               help for pubsub_cli
  -h, --host string        emulator host (You can also set 'PUBSUB_EMULATOR_HOST' to env variable) (default "pubsub:8085")
  -p, --project string     gcp project id (You can also set 'GCP_PROJECT_ID' to env variable)

Use "pubsub_cli [command] --help" for more information about a command.

[error] unknown shorthand flag: 'v' in -v

Maybe I missed it, but the -v argument does not seem to be listed in the cli's help or the doc either.

[k-yomo]

@ledouxpl
Sorry for the very late reply...! I couldn't reproduce the issue.
If still version command is not shown, could you share the environment and which binary you are using?

 pubsub_cli                                       ✔  16:54:36 
Very simple cloud Pub/Sub CLI used as publisher / subscriber

Usage:
  pubsub_cli [command]

Available Commands:
  completion          generate the autocompletion script for the specified shell
  connect             connect remote topics to local topics
  create_subscription create Pub/Sub subscription
  create_topic        create Pub/Sub topic
  help                Help about any command
  publish             publish Pub/Sub message
  register_push       register Pub/Sub push endpoint
  subscribe           subscribe Pub/Sub topics

Flags:
  -c, --cred-file string   gcp credential file path (You can also set 'GOOGLE_APPLICATION_CREDENTIALS' to env variable)
      --help               help for pubsub_cli
  -h, --host string        emulator host (You can also set 'PUBSUB_EMULATOR_HOST' to env variable)
  -p, --project string     gcp project id (You can also set 'GCP_PROJECT_ID' to env variable)
  -v, --version            version for pubsub_cli

Use "pubsub_cli [command] --help" for more information about a command.