README: Opening new issues

[Nightwalker-87]

In order to offer sufficient and the best possible support, please take note of the following:

1. If using a ST-Link-v2 programmer: Convince yourself that it is recognised as an USB device by your computer, thus reporting device and manufacturer ID. Use a diagnostic tool to probe for enumerated USB devices, e.g lsusb -v on unix-based systems.
2. Use the ST-Link firmware upgrade tool based on Java to read out the current firmware version and update to the latest available version. This also works for non-genuine ST programmers and boards.
3. Try to make sure you have a working toolchain before starting to build.
4. Update to the latest release version or maybe even use the develop branch.
5. Search for your problem in the available open issues, before opening a new ticket.
6. Make sure to use the available issue templates to submit a bug-report or a feature-request. Do not replace the prepared text, edit the placeholders instead. Describe your problem.
7. Avoid to add new comments to closed issues unless they confirm a solution already available.
8. Don't comment on tickets which do not specifically address your device or hardware - open a new ticket instead.
9. Consider if you can help to solve other issues (e.g. you have the same hardware)

NOTICE: Bug reports and/or feature request will be deleted, if no issue-template is used!

Thank you for your support.