Second commit adds addRawPotentialAction that adds potentialaction without actioncard/inputs. See for example https://messagecardplayground.azurewebsites.net/ and "Github - Issue opened" sample ("close" button). (This is an action where you can click on the button and msteams does POST straight away without showing any more buttons/actions).
This is related to issues 44/45. First commit adds optional _headers and _body parameters to addAction. (AFAIK these are relevant only for HttpPost action (https://docs.microsoft.com/en-us/outlook/actionable-messages/message-card-reference#httppost-action)).
Second commit adds addRawPotentialAction that adds potentialaction without actioncard/inputs. See for example https://messagecardplayground.azurewebsites.net/ and "Github - Issue opened" sample ("close" button). (This is an action where you can click on the button and msteams does POST straight away without showing any more buttons/actions).