Add instagram link

spec/22/index.yaml

@@ -13,6 +13,7 @@ links:
   discord: https://discord.gg/5k9dEtVhnv
   fbevent: https://www.facebook.com/events/276727151106692
   substack: https://utxoprague.substack.com/
+  instagram: https://www.instagram.com/utxoprague/
 specDef:
   - type: speakers
   - type: tracks