Replace string with another string with regexp in Ansible

This is the playbook which replaces param=[[number]] with newparam=19.

1.txt

test1 test2 param=13 test4

pl.yml

- name: Replace
  replace:
    path: ./1.txt
    regexp: '(param=)([0-9]{2}|[0-9]{1})'
    replace: 'newparam=19'