makeseeds: update MIN_BLOCKS, add reminder to README

Author: jonatack

contrib/seeds/README.md

@@ -8,6 +8,8 @@ and remove old versions as necessary (at a minimum when SeedsServiceFlags()
 changes its default return value, as those are the services which seeds are added
 to addrman with).
 
+Update `MIN_BLOCKS` in  `makeseeds.py` and the `-m`/`--minblocks` arguments below, as needed.
+
 The seeds compiled into the release are created from sipa's, achow101's and luke-jr's
 DNS seed, virtu's crawler, and asmap community AS map data. Run the following commands
 from the `/contrib/seeds` directory:

contrib/seeds/makeseeds.py

@@ -26,7 +26,7 @@
     'ipv6': 10,
 }
 
-MIN_BLOCKS = 840000
+MIN_BLOCKS = 868000
 
 PATTERN_IPV4 = re.compile(r"^((\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})):(\d+)$")
 PATTERN_IPV6 = re.compile(r"^\[([0-9a-z:]+)\]:(\d+)$")