feat(js): added async keyword to body's scripts tags

layouts/_default/baseof.html

@@ -35,10 +35,10 @@
 	{{ if .Site.Params.code_copy_button | default true -}}
 		{{ $codeCopy := resources.Get "js/code-copy.js" -}}
 		{{ $script := slice $main $codeCopy | resources.Concat "js/bundle.js" | minify | fingerprint -}}
-		<script src="{{ $script.Permalink }}" {{ printf "integrity=%q" $script.Data.Integrity | safeHTMLAttr }} crossorigin="anonymous"></script>
+		<script async src="{{ $script.Permalink }}" {{ printf "integrity=%q" $script.Data.Integrity | safeHTMLAttr }} crossorigin="anonymous"></script>
 	{{ else -}}
 		{{ $script := $main | minify | fingerprint -}}
-		<script src="{{ $script.Permalink }}" {{ printf "integrity=%q" $script.Data.Integrity | safeHTMLAttr }} crossorigin="anonymous"></script>
+		<script async src="{{ $script.Permalink }}" {{ printf "integrity=%q" $script.Data.Integrity | safeHTMLAttr }} crossorigin="anonymous"></script>
 	{{ end }}
 
 	{{- partial "analytics.html" . }}