Enable strict types and code cleanup

Summary:

* Enable PHP 7 strict types.
* Add header comments.
* Remove extra blank line in `composer.json`

Author: pH-7

composer.json

@@ -10,7 +10,6 @@
         "HTTP header"
     ],
     "homepage": "https://pierrehenry.be",
-
     "type": "library",
     "require": {
         "php": ">=8.0",

src/Exception.php

@@ -1,4 +1,8 @@
 <?php
+/**
+ * @author      Pierre-Henry Soria <hi@ph7.me>
+ * @license     MIT License
+ */
 
 namespace PH7\PhpHttpResponseHeader;
 

src/Http.php

@@ -1,4 +1,10 @@
 <?php
+/**
+ * @author      Pierre-Henry Soria <hi@ph7.me>
+ * @license     MIT License
+ */
+
+declare(strict_types=1);
 
 namespace PH7\PhpHttpResponseHeader;
 

tests/HttpTest.php

@@ -1,4 +1,8 @@
 <?php
+/**
+ * @author      Pierre-Henry Soria <hi@ph7.me>
+ * @license     MIT License
+ */
 
 declare(strict_types=1);