body and body_path do not preserve markdown formatting

[goerz]

body and body_path do not preserve markdown formatting

[tsekityam]

I can't reproduce this issue. I can use both body and body_path to set up the release message, and they are rendered in markdown format.

Here is the link to my demo repo: https://github.com/tsekityam/test-create-release-action

v1.0.0

Release with body with following values

Changes in this Release
- First Change
- Second Change

v2.0.0

Release with body_path set to CHANGELOG.md with the following value

This is the initial release of the `create-release` Action. This Action wraps the [create-release endpoint](https://developer.github.com/v3/repos/releases/#create-a-release) to create a [GitHub Release](https://help.github.com/en/articles/creating-releases).

- Updated tag/docs to match versioning for other Actions.