fix: preview logo was too small. (#2277)

## Issue Link / Problem Description
<!-- Link to related issue or describe the problem this PR solves -->
- linkedin might have ignored below 400x400 image size.

## Changes Made
<!-- Describe what you changed and why -->
- Changed og:image to a bigger ragas logo

Author: anistark

docs/extra/overrides/main.html

@@ -10,7 +10,7 @@
   {% if page and page.canonical_url %}<meta property="og:url" content="{{ page.canonical_url }}">{% endif %}
   <meta property="og:title" content="{% if page and page.title %}{{ page.title }} - {{ config.site_name }}{% else %}{{ config.site_name }}{% endif %}">
   <meta property="og:description" content="{% if page and page.meta and page.meta.description %}{{ page.meta.description }}{% else %}{{ config.site_description }}{% endif %}">
-  <meta property="og:image" content="{% if config.site_url %}{{ config.site_url }}{% endif %}{% if page and page.meta and page.meta.og_image %}{{ page.meta.og_image }}{% else %}_static/imgs/ragas-logo.png{% endif %}">
+  <meta property="og:image" content="{% if config.site_url %}{{ config.site_url }}{% endif %}{% if page and page.meta and page.meta.og_image %}{{ page.meta.og_image }}{% else %}_static/imgs/logo.png{% endif %}">
   <meta property="og:image:alt" content="Ragas - Evaluation framework for RAG pipelines">
   <meta property="og:site_name" content="{{ config.site_name }}">
 
@@ -19,7 +19,7 @@
   {% if page and page.canonical_url %}<meta property="twitter:url" content="{{ page.canonical_url }}">{% endif %}
   <meta property="twitter:title" content="{% if page and page.title %}{{ page.title }} - {{ config.site_name }}{% else %}{{ config.site_name }}{% endif %}">
   <meta property="twitter:description" content="{% if page and page.meta and page.meta.description %}{{ page.meta.description }}{% else %}{{ config.site_description }}{% endif %}">
-  <meta property="twitter:image" content="{% if config.site_url %}{{ config.site_url }}{% endif %}{% if page and page.meta and page.meta.og_image %}{{ page.meta.og_image }}{% else %}_static/imgs/ragas-logo.png{% endif %}">
+  <meta property="twitter:image" content="{% if config.site_url %}{{ config.site_url }}{% endif %}{% if page and page.meta and page.meta.og_image %}{{ page.meta.og_image }}{% else %}_static/imgs/logo.png{% endif %}">
   <meta property="twitter:site" content="@ragas_io">
   <meta property="twitter:creator" content="@ragas_io">