CI: Check repo for YosysHQ specific jobs

Prevents unintended bumps on the flake.lock and Yosys version on forks (provided the forks synchronize their main after this gets merged).
Update version.yml to use the same style of `if` on the job, rather than on specific actions.
Wheels will still build as a cron job, but won't try to upload if it's a fork.

.github/workflows/update-flake-lock.yml

@@ -6,6 +6,7 @@ on:
 
 jobs:
   lockfile:
+    if: github.repository == 'YosysHQ/Yosys'
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repository