[Github] Create reminder message to manually start workflow

[vbvictor]

In projects with high or very little number of first-time contributors, it's easy to forget to approve CI workflows that will test code and check formatting. This increases the chance of pushing untested code into main.

I suggest creating a notification message what will remind maintainers to accept workflows.
The implementation may be similar to "private email detected" runner, It will be a single message that will encourage maintainers to approve workflows.

Here is how it looks in one of the nvidia repositories: NVIDIA/numbast#80.

Should this change go through an RFC in discourse? If not, I could try to implement this or put up an RFC otherwise.