fix: use testing in the example

Author: not-matthias

example/fib_test.go

@@ -1,6 +1,6 @@
 package example
 
-import testing "github.com/AvalancheHQ/codspeed-go/compat/testing"
+import "testing"
 
 func BenchmarkFibonacci10(b *testing.B) {
 	for i := 0; i < b.N; i++ {

example/go.mod

@@ -1,7 +1,3 @@
 module example
 
 go 1.24.3
-
-require github.com/AvalancheHQ/codspeed-go v0.0.0
-
-replace github.com/AvalancheHQ/codspeed-go => ..