CI: grant release job explicit contents:write permission

The 0.1.0 tag push triggered the Windows release workflow but it
failed at the "Upload release artifacts" step with:

    HTTP 403: Resource not accessible by integration
    (https://api.github.com/repos/iliaal/mdparser/releases)

Two fixes:

1. Bumped the repo-level default workflow permission from `read`
   to `write` (matches iliaal/php_excel's setting). New GitHub
   repos default to `read`, which blocks release creation.

2. Added an explicit `permissions: contents: write` block on the
   `release` job in windows.yml as self-documentation. The
   php-windows-builder/release@v1 action calls POST /releases
   which requires contents write scope.

Both were necessary; belt and suspenders. Retagging 0.1.0 at the
new HEAD so the release build runs against this fix.

Author: iliaal

.github/workflows/windows.yml

@@ -43,6 +43,11 @@ jobs:
     if: startsWith(github.ref, 'refs/tags/')
     needs: windows-build
     runs-on: ubuntu-latest
+    # Explicit write scope for releases; default GITHUB_TOKEN is read-only
+    # for the contents permission on newly-created repos and the
+    # php-windows-builder/release@v1 action calls POST /releases.
+    permissions:
+      contents: write
     steps:
       - uses: actions/checkout@v6