feat: add versioning setup

layouts/_default/versions.html

@@ -0,0 +1,27 @@
+{{ define "main" }}
+  <article>
+    <h1>{{ .Title }}</h1>
+    <p class="lead">{{ .Params.lead | safeHTML }}</p>
+    {{ .Content }}
+    <div class="row">
+      {{ range $release := sort (index $.Site.Data "docs-versions") "group" "desc" -}}
+      <div class="col-md-8 col-lg-4 col-xl mb-4">
+        <h2>{{ $release.group }}</h2>
+        <p>{{ $release.description }}</p>
+        {{ $versions := sort $release.versions "v" "desc" -}}
+        {{ range $i, $version := $versions -}}
+          {{ $len := len $versions -}}
+          {{ if (eq $i 0) }}<div class="list-group">{{ end }}
+            <a class="list-group-item list-group-item-action py-2 text-primary{{ if (eq $version.v $.Site.Params.docsVersion) }} d-flex justify-content-between align-items-center{{ end }}" href="{{ $release.baseurl }}/{{ $version.v }}/">
+              {{ $version.v }}
+              {{ if (eq $version.v $.Site.Params.docsVersion) -}}
+              <span class="badge bg-primary">Latest</span>
+              {{ end -}}
+            </a>
+          {{ if (eq (add $i 1) $len) }}</div>{{ end }}
+        {{ end -}}
+      </div>
+      {{ end -}}
+    </div>
+  </article>
+{{ end }}