update README.md with a clarification.

[bogacyigitbasi]

Purpose

_Describe the purpose of the pull request, link to issue describing the problem, etc.

Changes

_Describe the changes that were needed.

Checklist

• My code follows the style of this project.
• The code compiles without warnings.
• I have performed a self-review of the changes.
• I have documented my code, in particular the intent of the
  hard-to-understand areas.
• (If necessary) I have updated the CHANGELOG.

CLA acceptance

_Remove if not applicable.

By submitting the contribution I accept the terms and conditions of the
Contributor License Agreement v1.0

• link: https://developers.concordium.com/CLAs/Contributor-License-Agreement-v1.0.pdf

• I accept the above linked CLA.

[DOBEN]

Suggested change

	- If you are going to start building a bounty task, please comment on the issue so that others can track it. If you declared and submitted anything, or haven't shown any progress for a long time Concordium team has a right to give the task to any other volunteer. From that moment first come first serve will apply.
	- If you are going to start building a bounty task, please comment on the issue so that others can track it. If you commented on the issue but haven't submitted anything, or haven't shown any progress for a long time Concordium team has a right to give the task to any other volunteer. From that moment first come first serve will apply.