added changelog and fixed type issues

Author: oscarotero

CHANGELOG.md

@@ -0,0 +1,12 @@
+# Change Log
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](http://keepachangelog.com/) 
+and this project adheres to [Semantic Versioning](http://semver.org/).
+
+Previous releases are documented in [github releases](https://github.com/oscarotero/Gettext/releases)
+
+## [1.0.0] - Unreleased
+
+First version

src/PhpFunctionsScanner.php

@@ -18,7 +18,7 @@ public function __construct(array $validFunctions = null, Parser $parser = null)
         $this->parser = $parser ?: (new ParserFactory())->create(ParserFactory::PREFER_PHP7);
     }
 
-    public function scan(string $code, string $filename = null): array
+    public function scan(string $code, string $filename): array
     {
         $ast = $this->parser->parse($code);
 

src/PhpNodeVisitor.php

@@ -14,7 +14,7 @@ class PhpNodeVisitor implements NodeVisitor
     protected $filename;
     protected $functions = [];
 
-    public function __construct(string $filename = null, array $validFunctions = null)
+    public function __construct(string $filename, array $validFunctions = null)
     {
         $this->filename = $filename;
         $this->validFunctions = $validFunctions;