website: hardcode version banner for 0.1 docs

O.1 docs is deprecated. Let's inform user to switch the the latest version

Signed-off-by: user.email <jf@dagger.io>

website/src/components/DeprecatedVersionBanner.js

@@ -0,0 +1,12 @@
+import React from 'react'
+
+function DeprecatedVersionBanner() {
+  return (
+      <div class="theme-doc-version-banner alert alert--warning margin-bottom--md" role="alert">
+        <div>This is documentation for Dagger <b>0.1</b>, which is no longer actively maintained.</div>
+        <div class="margin-top--md">For up-to-date documentation, see the <b><a href="/">latest version</a></b> (0.2).</div>
+      </div>
+  )
+}
+
+export default DeprecatedVersionBanner

website/src/theme/DocPage/index.js

@@ -27,6 +27,7 @@ import {
 } from '@docusaurus/theme-common';
 import Head from '@docusaurus/Head';
 import amplitude from 'amplitude-js';
+import DeprecatedVersionBanner from '../../components/DeprecatedVersionBanner';
 
 function DocPageContent({
   currentDocRoute,
@@ -171,6 +172,9 @@ function DocPage(props) {
             currentDocRoute={currentDocRoute}
             versionMetadata={versionMetadata}
             sidebarName={sidebarName}>
+            {currentDocRoute.sidebar === '0.1' && (
+            <DeprecatedVersionBanner />
+            )}
             <div data-cy="cy-doc-content">
               {renderRoutes(docRoutes, {
                 versionMetadata,