Upgrading

• #1427 / #1373 / #1371 - fix staticcheck warnings, remove support for gobindata / go 1.16

Features:

• #1473 - nsqd: use --tls-root-ca-file in nsqauth request (thanks @intellitrend-team)
• #1470 / #1469 - nsqadmin: upgrade supported ECMA from ES5 to ES2020 (thanks @dudleycarr)
• #1468 - nsqadmin: add paused label to topic within the node view (thanks @dudleycarr)
• #1462 - nsqadmin: add admin check for topic/node thombstone endpoint (thanks @dudleycarr)
• #1434 - nsqd: add support of unix sockets for tcp, http, https listeners (thanks @telepenin)
• #1424 - nsqd: add /debug/freememory API (thanks @guozhao-coder)
• #1421 - nsqd: nicer tls-min-version help text default
• #1376 - nsqd: allow unbuffered memory chan if ephemeral or deferred
• #1380 - nsqd: use metadata struct for both marshal and unmarshal (thanks @karalabe)
• #1403 - nsqd: /info api returns more info (thanks @arshabbir)