update weightedrand module to v2

Author: mroth

README.md

@@ -16,7 +16,7 @@ element to be selected are not equal, but rather defined by relative "weights"
 ```go
 import (
     /* ...snip... */
-    "github.com/mroth/weightedrand"
+    "github.com/mroth/weightedrand/v2"
 )
 
 func main() {
@@ -73,6 +73,11 @@ right choice! If you are only picking from the same distribution once,
 `randutil` will be faster. `weightedrand` optimizes for repeated calls at the
 expense of some initialization time and memory storage.
 
+## Requirements
+
+weightedrand >= v2 requires go1.18 or greater. For support on earlier versions
+of go, use weightedrand [v1](https://github.com/mroth/weightedrand/tree/v1).
+
 ## Credits
 
 To better understand the algorithm used in this library (as well as the one used

examples/compbench/bench_test.go

@@ -9,7 +9,7 @@ import (
 	"time"
 
 	"github.com/jmcvetta/randutil"
-	"github.com/mroth/weightedrand"
+	"github.com/mroth/weightedrand/v2"
 )
 
 const BMMinChoices = 10
@@ -98,9 +98,9 @@ func BenchmarkSingle(b *testing.B) {
 	})
 }
 
-func mockChoices(tb testing.TB, n int) []weightedrand.Choice {
+func mockChoices(tb testing.TB, n int) []weightedrand.Choice[rune, uint] {
 	tb.Helper()
-	choices := make([]weightedrand.Choice, 0, n)
+	choices := make([]weightedrand.Choice[rune, uint], 0, n)
 	for i := 0; i < n; i++ {
 		s := '🥑'
 		w := rand.Intn(10)
@@ -110,7 +110,7 @@ func mockChoices(tb testing.TB, n int) []weightedrand.Choice {
 	return choices
 }
 
-func convertChoices(tb testing.TB, cs []weightedrand.Choice) []randutil.Choice {
+func convertChoices(tb testing.TB, cs []weightedrand.Choice[rune, uint]) []randutil.Choice {
 	tb.Helper()
 	res := make([]randutil.Choice, len(cs))
 	for i, c := range cs {

examples/compbench/go.mod

@@ -1,10 +1,10 @@
 module github.com/mroth/weightedrand/examples/compbench
 
-go 1.15
+go 1.18
 
 require (
 	github.com/jmcvetta/randutil v0.0.0-20150817122601-2bb1b664bcff
-	github.com/mroth/weightedrand v0.0.0
+	github.com/mroth/weightedrand/v2 v2.0.0
 )
 
-replace github.com/mroth/weightedrand => ../..
+replace github.com/mroth/weightedrand/v2 => ../..

examples/frequency/main.go

@@ -6,7 +6,7 @@ import (
 	"math/rand"
 	"time"
 
-	"github.com/mroth/weightedrand"
+	"github.com/mroth/weightedrand/v2"
 )
 
 func main() {

go.mod

@@ -1,3 +1,3 @@
-module github.com/mroth/weightedrand
+module github.com/mroth/weightedrand/v2
 
 go 1.18