There are two problems with self-hosted runners:

1. Every run creates a new docker image.
2. A container is run as root user, that causes some problems with the files in future runs

The first problem is solved by building a docker image and referencing it in a workflow:

- name: 'Create pull request'
  uses: docker://ghcr.io/tegorov/pull-request:v2.6.2
  with:
     source_branch: develop
  ...

The second problem is solved by passing USER_ID parameter in a container:

- name: 'Create pull request'
  uses: docker://ghcr.io/tegorov/pull-request:v2.6.2
  with:
     source_branch: develop
     ...
  env:
     USER_ID: 1000

Here is my pull request as an example #90