What is the correct syntax of defining role dependencies in the meta/main.yml in Ansible?

Updating the meta/main.yml according this snippet as follows:

dependencies:
  - src: 030.firewall
    version: 0.1.0
    name: 030.firewall
  - src: 030.sensu-client
    version: 0.4.1
    name: 030.sensu-client
  - src: geerlingguy.ntp
    version: 1.3.0
    name: geerlingguy.ntp    
  - src: geerlingguy.postfix
    version: 1.1.0
    name: geerlingguy.postfix
  - src: geerlingguy.redis
    version: 1.4.1
    name: geerlingguy.redis
  - src: Stouts.rabbitmq
    version: 1.2.1
    name: Stouts.rabbitmq

and installing the requirements by issuing ansible-galaxy install -r requirements/development.yml did not return the [DEPRECATION WARNING]: The comma separated role spec format issue anymore.

There is open bugfix pull request on github regarding this issue but its still unclear if its a bug or you should use src: instead, check the discussion.

https://github.com/ansible/ansible/pull/14612

I guess until the devs make up their minds you can ignore that warning. Moreover you are not really using comma separated syntax, so this warning should not appear in my opinion.

dependencies:
    - { role: 030.sensu-install }

should be ok.