feat: open graph meta tags (#871)

* Added open graph meta tags ( Facebook )

* feat : add a preview image for website.

The image would act as a site preview across social networks.

* Updated head.pug for suggested changes.

Replaced "name" field in meta tags with "property", And replaced the og:image field value to a relative image path.

* Added twitter open graph meta tags.

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Co-authored-by: Pulkit Saini <54940154+pulbee@users.noreply.github.com>

src/pug/includes/head.pug

@@ -7,6 +7,19 @@ meta(http-equiv="X-UA-Compatible" content="IE=edge")
 
 meta(name="description" content="swag opportunities for developers")
 
+meta(property="og:site_name" content="devSwag")
+meta(property="og:title" content="devSwag")
+meta(property="og:url" content="https://devswag.io/")
+meta(property="og:type" content="website")
+meta(property="og:description" content="swag opportunities for developers")
+meta(property="og:image" content="/assets/img/devswag-card.png")
+
+meta(property="twitter:card" content="summary_large_image")
+meta(property="twitter:title" content="devSwag")
+meta(property="twitter:url" content="https://devswag.io/")
+meta(property="twitter:description" content="swag opportunities for developers")
+meta(property="twitter:image" content="/assets/img/devswag-card.png")
+
 link(rel="icon" type="image/png" href="/assets/img/logo.png")
 link(rel="apple-touch-icon" size="128x128" href="/assets/img/logo.png")