[github-maintenance] Fix pnpm-workspace.yaml configuration (#112)

Adds missing `pnpm-workspace.yaml` with required fields.

See the tracking issue in github-maintenance.

<!-- github-maintenance:hash=3d5358e2:script=pnpm-workspace-check -->

Co-authored-by: marimo-github-maintenance-bot[bot] <267743655+marimo-github-maintenance-bot[bot]@users.noreply.github.com>

Author: marimo-github-maintenance-bot[bot]

pnpm-workspace.yaml

@@ -0,0 +1,4 @@
+minimumReleaseAge: 10080
+verifyDepsBeforeRun: install
+minimumReleaseAgeExclude:
+  - "@marimo-team/*"