feat: add rel=me to social links (#707)

Adds rel-me to social links

[rel="me"] is a commonly used way to show that that two websites or
social
media accounts are the same, and is used for authentication and proving
site ownership in a variety of ways.

[rel="me"]: https://indieweb.org/rel-me

layouts/partials/sidebar/left.html

@@ -45,6 +45,7 @@
                         href='{{ .URL }}'
                         {{ if eq (default true .Params.newTab) true }}target="_blank"{{ end }}
                         {{ with .Name }}title="{{ . }}"{{ end }}
+                        rel="me"
                     >
                         {{ $icon := default "link" .Params.Icon }}
                         {{ with $icon }}