Restructure linkcheck matrix per review

Author: konstin

.github/workflows/test.yml

@@ -25,17 +25,18 @@ jobs:
     if: ${{ github.repository_owner == 'pypa' || github.event_name != 'schedule' }}
     runs-on: ubuntu-latest
     timeout-minutes: 20
-    # Don't block PRs on linkcheck unrelated failures
-    continue-on-error: ${{ matrix.ignore-errors || false }}
+    continue-on-error: >-
+      ${{ fromJSON(matrix.continue-on-error) }}
     strategy:
-      fail-fast: false
       matrix:
         noxenv:
         - build
-        - linkcheck
+        continue-on-error:
+        - false
         include:
         - noxenv: linkcheck
-          ignore-errors: true
+          continue-on-error: >-  # Don't block PRs on linkcheck unrelated failures
+            ${{ toJSON(github.event_name == 'pull_request') }}
 
     steps:
       - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0