issue: nvim-lua#594 stylua workflow only on official kickstart repo

Only run the github stylua workflow check on the official
kickstart repo (nvim-lua/kickstart.nvim) so that it's not
enforced on any other forks.
As suggested by: @zwergius

.github/workflows/stylua.yml

@@ -4,6 +4,7 @@ on: pull_request_target
 
 jobs:
   stylua-check:
+    if: github.repository == 'nvim-lua/kickstart.nvim'
     name: Stylua Check
     runs-on: ubuntu-latest
     steps: