trying again with go version / go mod tidy

Author: johnkerl

.github/workflows/release.yml

@@ -6,7 +6,7 @@ on:
   workflow_dispatch:
 
 env:
-  GO_VERSION: 1.19.13
+  GO_VERSION: 1.21.1
 
 jobs:
   release:

go.mod

@@ -14,7 +14,7 @@ module github.com/johnkerl/miller/v6
 // Local development:
 // replace github.com/johnkerl/lumin => /Users/kerl/git/johnkerl/lumin
 
-go 1.20
+go 1.21
 
 require (
 	github.com/facette/natsort v0.0.0-20181210072756-2cd4dd1e2dcb