Update Görli bootnodes. (#1842)

Signed-off-by: Adrian Sutton <adrian.sutton@consensys.net>

ethereum/p2p/src/main/java/tech/pegasys/pantheon/ethereum/p2p/config/DiscoveryConfiguration.java

@@ -73,8 +73,7 @@ public class DiscoveryConfiguration {
                   "enode://011f758e6552d105183b1761c5e2dea0111bc20fd5f6422bc7f91e0fabbec9a6595caf6239b37feb773dddd3f87240d99d859431891e4a642cf2a0a9e6cbb98a@51.141.78.53:30303",
                   "enode://176b9417f511d05b6b2cf3e34b756cf0a7096b3094572a8f6ef4cdcb9d1f9d00683bf0f83347eebdf3b81c3521c2332086d9592802230bf528eaf606a1d9677b@13.93.54.137:30303",
                   "enode://46add44b9f13965f7b9875ac6b85f016f341012d84f975377573800a863526f4da19ae2c620ec73d11591fa9510e992ecc03ad0751f53cc02f7c7ed6d55c7291@94.237.54.114:30313",
-                  "enode://c1f8b7c2ac4453271fa07d8e9ecf9a2e8285aa0bd0c07df0131f47153306b0736fd3db8924e7a9bf0bed6b1d8d4f87362a71b033dc7c64547728d953e43e59b2@52.64.155.147:30303",
+                  "enode://b5948a2d3e9d486c4d75bf32713221c2bd6cf86463302339299bd227dc2e276cd5a1c7ca4f43a0e9122fe9af884efed563bd2a1fd28661f3b5f5ad7bf1de5949@18.218.250.66:30303")
-                  "enode://f4a9c6ee28586009fb5a96c8af13a58ed6d8315a9eee4772212c1d4d9cebe5a8b8a78ea4434f318726317d04a3f531a1ef0420cf9752605a562cfe858c46e263@213.186.16.82:30303")
               .map(EnodeURL::fromString)
               .collect(toList()));