og:url still has trailing /index.html even when cleanUrl is true in site cofnig

[ForbesLindesay]

🐛 Bug Report

og:url still has trailing /index.html even when cleanUrl is true in site cofnig

Have you read the [Contributing Guidelines on issues]

yes

To Reproduce

1. Create a new site using docusarus
2. set cleanUrl to true
3. set url: 'https://www.bicyclejs.org'
4. build the site

Expected behavior

The header should contain:

<meta property="og:url" content="https://www.bicyclejs.org">

Actual Behavior

The header contains:

<meta property="og:url" content="https://www.bicyclejs.org/index.html">

Reproducible Demo

https://github.com/bicyclejs/bicycle

1. cd website
   2.yarn
2. yarn start
3. Open your browser and inspect the page
4. Notice the og:url tag has an erroneous /index.html on the end