Cleanup references to NewWith

Author: Paweł Rozynek

README.md

@@ -39,7 +39,7 @@ defer m.Log()
 
 Customizing the logger:
 ```
-emf.NewWith(
+emf.New(
     emf.WithWriter(os.Stderr), // Log to stderr.
     emf.WithTimestamp(time.Now().Add(-time.Hour)), // Record past metrics.
 )

emf/logger.go

@@ -44,7 +44,7 @@ func WithTimestamp(t time.Time) LoggerOption {
 // New creates logger with reasonable defaults for Lambda functions:
 // - Prints to os.Stdout.
 // - Context based on Lambda environment variables.
-// - Timestamp set to the time when NewWith was called.
+// - Timestamp set to the time when New was called.
 // Specify LoggerOptions to customize the logger.
 func New(opts ...LoggerOption) *Logger {
 	values := make(map[string]interface{})