Merge #20660: Move signet onion seed from v2 to v3

3e6657a Move signet onion seed from v2 to v3 (Sjors Provoost)

Pull request description:

  Since v0.21 hidden services use the longer v3 address format.

  It may make sense to backport this to the v0.21 branch, although onion nodes can always use the non-onion seeds.

ACKs for top commit:
  MarcoFalke:
    Concept ACK 3e6657a
  laanwj:
    ACK 3e6657a
  Saibato:
    tACK bitcoin/bitcoin@3e6657a  👍

Tree-SHA512: 9bb4d82345ab25d6ea971f8f106c30778ade2ba11a292e8d7449ea39581b91e51c4b34851b5c06f5dfbe07e7b04e5dc92c48c98c47a1c7ef3d5f350c3a3ad4f7

Author: laanwj

src/chainparams.cpp

@@ -272,7 +272,7 @@ class SigNetParams : public CChainParams {
             bin = ParseHex("512103ad5e0edad18cb1f0fc0d28a3d4f1f3e445640337489abb10404f2d1e086be430210359ef5021964fe22d6f8e05b2463c9540ce96883fe3b278760f048f5189f2e6c452ae");
             vSeeds.emplace_back("178.128.221.177");
             vSeeds.emplace_back("2a01:7c8:d005:390::5");
-            vSeeds.emplace_back("ntv3mtqw5wt63red.onion:38333");
+            vSeeds.emplace_back("v7ajjeirttkbnt32wpy3c6w3emwnfr3fkla7hpxcfokr3ysd3kqtzmqd.onion:38333");
 
             consensus.nMinimumChainWork = uint256S("0x00000000000000000000000000000000000000000000000000000019fd16269a");
             consensus.defaultAssumeValid = uint256S("0x0000002a1de0f46379358c1fd09906f7ac59adf3712323ed90eb59e4c183c020"); // 9434