DEVOPS-2496 add max history setting (#12)

* add history_max setting

* update docs

* use suite for env test

internal/env/testing.go

@@ -0,0 +1,15 @@
+package env
+
+import (
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func NewTestConfig(t *testing.T) *Config {
+	conf, err := NewConfig(os.Stdout, os.Stderr)
+	require.NoError(t, err)
+
+	return conf
+}