Github Action: Fix exit status

[forslund]

Currently master will show an angry red X if the version was not changed. This is due to the fact that the tag-if-needed will not set the version and lazily just report that all is good leading to the Create Mycroft-core PR stage triggering without the version output from the previous stage being set, leading to an invalid version being detected.

Not sure what the best action is, if we move the setting of the version output earlier it should work but looks a bit like the next stage would try to create a PR even if the version didn't change.

Another way would be to mark the stages to be allowed to fail.

Best would be if there is a way to set a conditional and only continue to run the following step if a conditional was set.

I will try to look into it during the week but posting here as an explanation for the current red X on master. (and if anyone else feels like digging into it)