fix(gateway): update DoH resolver for .crypto DNSLink (#782)

fix(gateway): update DoH resolver for .crypto TLD

Cloudflare decomissionned their resolver and started redirecting
(HTTP 308) to https://dns.eth.link/dns-query which is an alias for
eth.limo.

That endpoint does not support resolving DNSLink of .crypto TLD and
always returns no results.

This change switched to DoH resolver provided by UD project.

See  #772 for more info and the future of .crypto resolver

CHANGELOG.md

@@ -25,6 +25,7 @@ The following emojis are used to highlight certain changes:
 ### Fixed
 
 - `gateway` Fix redirect URLs for subdirectories with characters that need escaping. [#779](https://github.com/ipfs/boxo/pull/779)
+- `gateway` The default DNSLink resolver for `.crypto` TLD changed to `https://resolver.unstoppable.io/dns-query` [#782](https://github.com/ipfs/boxo/pull/782)
 
 ### Security
 

gateway/dns.go

@@ -11,7 +11,7 @@ import (
 
 var defaultResolvers = map[string]string{
 	"eth.":    "https://dns.eth.limo/dns-query",
-	"crypto.": "https://resolver.cloudflare-eth.com/dns-query",
+	"crypto.": "https://resolver.unstoppable.io/dns-query",
 }
 
 func newResolver(url string, opts ...doh.Option) (madns.BasicResolver, error) {