use API v2 as default

"Version 1 (v1) of the DeepL API is not supported by the DeepL API plan available from October 2018. Please use version 2 for all new products other than CAT tool integrations."
from https://www.deepl.com/docs-api/accessing-the-api/api-versions/

src/DeepL.php

@@ -132,7 +132,7 @@ class DeepL
      * @param string  $authKey
      * @param integer $apiVersion
      */
-    public function __construct($authKey, $apiVersion = 1)
+    public function __construct($authKey, $apiVersion = 2)
     {
         $this->authKey    = $authKey;
         $this->apiVersion = $apiVersion;
@@ -251,7 +251,7 @@ protected function buildUrl(
                 $url = DeepL::API_URL_V2;
                 break;
             default:
-                $url = DeepL::API_URL_V1;
+                $url = DeepL::API_URL_V2;
         }
 
         $url .= '?' . sprintf(DeepL::API_URL_AUTH_KEY, $this->authKey);

tests/DeepLTest.php

@@ -106,7 +106,7 @@ public function testBuildUrl()
     {
         $authKey = '123456';
 
-        $expectedString = 'https://api.deepl.com/v1/translate?' . http_build_query(array(
+        $expectedString = 'https://api.deepl.com/v2/translate?' . http_build_query(array(
             'auth_key' => $authKey,
             'source_lang' => 'de',
             'target_lang' => 'en',
@@ -128,7 +128,7 @@ public function testBuildUrl()
     public function testBuildUrlWithTags()
     {
         $authKey = '123456';
-        $expectedString = 'https://api.deepl.com/v1/translate?' . http_build_query(array(
+        $expectedString = 'https://api.deepl.com/v2/translate?' . http_build_query(array(
             'auth_key' => $authKey,
             'source_lang' => 'de',
             'target_lang' => 'en',
@@ -164,7 +164,7 @@ public function testBuildBody()
     }
 
     /**
-     * Test translate() success
+     * Test translate() success with v2 API
      *
      * TEST REQUIRES VALID DEEPL AUTH KEY!!
      */
@@ -185,17 +185,17 @@ public function testTranslateSuccess()
     }
 
     /**
-     * Test translate() success with v2 API
+     * Test translate() success with v1 API
      *
      * TEST REQUIRES VALID DEEPL AUTH KEY!!
      */
-    public function testTranslateV2Success()
+    public function testTranslateV1Success()
     {
         if (self::$authKey === false) {
             $this->markTestSkipped('DeepL Auth Key (DEEPL_AUTH_KEY) is not configured.');
         }
 
-        $deepl = new DeepL(self::$authKey, 2);
+        $deepl = new DeepL(self::$authKey, 1);
 
         $germanText     = 'Hallo Welt';
         $expectedText   = 'Hello World';