feat(info): indicate OpenAPI 2.0 definition version (#9167)

src/core/components/info.jsx

@@ -89,6 +89,7 @@ class Info extends React.Component {
     const Markdown = getComponent("Markdown", true)
     const Link = getComponent("Link")
     const VersionStamp = getComponent("VersionStamp")
+    const OpenAPIVersion = getComponent("OpenAPIVersion")
     const InfoUrl = getComponent("InfoUrl")
     const InfoBasePath = getComponent("InfoBasePath")
     const License = getComponent("License")
@@ -99,7 +100,8 @@ class Info extends React.Component {
         <hgroup className="main">
           <h2 className="title">
             {title}
-            {version && <VersionStamp version={version}></VersionStamp>}
+            {version && <VersionStamp version={version} />}
+            <OpenAPIVersion oasVersion="2.0" />
           </h2>
           {host || basePath ? (
             <InfoBasePath host={host} basePath={basePath} />

src/core/components/openapi-version.jsx

@@ -0,0 +1,15 @@
+import React from "react"
+import PropTypes from "prop-types"
+
+
+const OpenAPIVersion = ({ oasVersion }) => (
+  <small className="version-stamp">
+    <pre className="version">OAS {oasVersion}</pre>
+  </small>
+)
+
+OpenAPIVersion.propTypes = {
+  oasVersion: PropTypes.string.isRequired
+}
+
+export default OpenAPIVersion