how to write plain text to github_step_output and strip markdown?

Question

I am trying to report pytest test coverage in github actions step summary as below:

    steps:
      etc...
      etc...
      - name: pytest-cov
        run: pytest --cov=app tests/  >> $GITHUB_STEP_SUMMARY

it is working successfully. However, the pytest --cov=app tests/ is something like this:

---------- coverage: platform darwin, python 3.9.6-final-0 -----------
Name                                    Stmts   Miss  Cover
-----------------------------------------------------------
app/__init__.py                             0      0   100%
etc...
etc...
-----------------------------------------------------------
TOTAL                                    1551    708    54%

and it is being treated as markdown and that is why the format of the table is not what I see here. it is kind of distorted.

I did some research and found this https://github.com/vector-im/element-meta/issues/1189 and there is /plain option to be added to the beginning of the message but I don't understand how should it be done.

what should I do in pytest --cov=app tests/ >> $GITHUB_STEP_SUMMARY so that the coverage report table prints properly?