Parse brew list for the version of currently installed cowsay.

cowsay.yml

---

- hosts: localhost
  connection: local

  tasks:
    - name: Install cowsay.
      homebrew:
        name: cowsay

    - name: brew list cowsay
      command: brew list cowsay
      register: cowsay_return

    - name: /usr/local/Cellar/cowsay/3.04/INSTALL_RECEIPT.json
      debug:
        var: cowsay_return.stdout_lines[0]

    - name: Look for installed cowsay version number.
      set_fact:
        version: "{{ cowsay_return.stdout_lines[0] | regex_search('(\\d+\\.\\d+)') }}"

    - name: 3.04
      debug:
        var: version

    - name: Install buffalo cow.
      get_url:
        url: https://gist.githubusercontent.com/deekayen/8a8e3fc22a7a84a35ada9dd9b4703b27/raw/c9515612afa387dc6d4445bace9ebcd0738cad99/buffalo.cow
        dest: "/usr/local/Cellar/cowsay/{{ version }}/share/cows/buffalo.cow"

    - name: Update local user ansible config to use buffalo.
      ini_file:
        path: ~/.ansible.cfg
        section: defaults
        option: cow_selection
        value: buffalo
        mode: 0644

Run this like:

ansible-playbook -i localhost, cowsay.yml