chore: prep for v0.21.0 (#1717)

Prep work for the v0.21.0 release. The `current` version in
`versions/versions.json` will be updated after this is live on testntet
as it only impacts docs.
The seeds for testnet 7 are included in #1681, which will be merged once
we're ready to have the public launch testnet 7 nodes.

Author: PoisonPhang

flake.lock

@@ -123,6 +123,10 @@
       url = "github:unionlabs/union/release-v0.20.0";
       flake = false;
     };
+    v0_21_0 = {
+      url = "github:unionlabs/union/release-v0.21.0";
+      flake = false;
+    };
   };
   outputs =
     inputs@{ self

flake.nix

@@ -87,7 +87,7 @@
           mkBundle {
             name = "testnet-next";
             versions = uniondBundleVersions.complete;
-            nextVersion = "v0.21.0";
+            nextVersion = "v0.22.0";
             genesis = ../networks/genesis/union-testnet-7/genesis.json;
             meta = {
               binary_name = "uniond";

unionvisor/unionvisor.nix

@@ -15,7 +15,7 @@
     "seeds": "b37de4c50e26f7cde4c7b6ce06046a6693ffef2c@union.testnet.6.seed.poisonphang.com:26656"
   },
   "union-testnet-7": {
-    "versions": ["v0.20.0"],
+    "versions": ["v0.20.0", "v0.21.0"],
     "current": "v0.20.0",
     "seeds": ""
   }