fix: change url and label name for "good-first-issue" on CONTRIBUTING.md
There isn't a label named "good first issue" but named "good-first-issue" on this repo. So I fixed the link on CONTRIBUTING.md.
@@ -44,7 +44,7 @@ relevant Issues.
To make yourself comfortable with the code, you might want to work on some
Issues marked with one or more of the following labels:
-[good first issue](https://github.com/kubevirt/kubevirt/labels/good%20first%20issue),
+[good-first-issue](https://github.com/kubevirt/kubevirt/labels/good-first-issue),
[help wanted](https://github.com/kubevirt/kubevirt/labels/help%20wanted)
or [kind/bug](https://github.com/kubevirt/kubevirt/labels/kind%2Fbug).
Any help is highly appreciated.
