linting fixes

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

config/loader/memory/memory.go

@@ -193,6 +193,7 @@ func (m *memory) Snapshot() (*loader.Snapshot, error) {
 
 // Sync loads all the sources, calls the parser and updates the config
 func (m *memory) Sync() error {
+	//nolint:prealloc
 	var sets []*source.ChangeSet
 
 	m.Lock()

config/options/options.go

@@ -2,6 +2,7 @@
 package options
 
 import (
+	"log"
 	"sync"
 )
 
@@ -68,6 +69,8 @@ func WithString(s string) Option {
 // NewOptions returns a new initialiser
 func NewOptions(opts ...Option) Options {
 	o := new(defaultOptions)
-	o.Init(opts...)
+	if err := o.Init(opts...); err != nil {
+		log.Fatal(err)
+	}
 	return o
 }

config/source/env/options.go

@@ -35,6 +35,7 @@ func WithPrefix(p ...string) source.Option {
 }
 
 func appendUnderscore(prefixes []string) []string {
+	//nolint:prealloc
 	var result []string
 	for _, p := range prefixes {
 		if !strings.HasSuffix(p, "_") {