The workflow is not valid. .github/workflows/tests.yml (Line: 15, Col: 27): Unrecognized named-value: 'MAILGUN_DOMAIN'. Located at position 1 within expression: MAILGUN_DOMAIN .github/workflows/tests.yml (Line: 16, Col: 24): Unrecognized named-value: 'MAILGUN_KEY'. Located at position 1 within expression: MAILGUN_KEY