Fix documentation date capture: use full git history in pages workflow

The pages workflow used the default shallow clone (fetch-depth: 1),
which only fetches the latest commit. git log --follow therefore saw
only one commit per file, making created == updated == today.

Adding fetch-depth: 0 gives the full repository history so git
timestamps correctly reports the oldest commit as created and the
newest commit as last-updated.

Signed-off-by: Copilot <copilot@github.com>

Agent-Logs-Url: https://github.com/onnxruntime/mobius/sessions/5f272c31-b070-420b-9ee7-7da1f8930821

Co-authored-by: justinchuby <11205048+justinchuby@users.noreply.github.com>

Author: Copilot

.github/workflows/pages.yml

@@ -23,6 +23,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v6
+        with:
+          fetch-depth: 0
 
       - name: Setup Python
         uses: actions/setup-python@v6