fix: Fix getUsage HTTP request

Author: JanEbbing

CHANGELOG.md

@@ -7,6 +7,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## Unreleased 
 ### Fixed
 * Changed document translation to poll the server every 5 seconds. This should greatly reduce observed document translation processing time.
+* Fix getUsage request to be a HTTP GET request, not POST.
 
 
 ## [1.2.0] - 2023-03-22

deepl-java/src/main/java/com/deepl/api/Translator.java

@@ -247,7 +247,7 @@ public List<TextResult> translateText(
    * @throws DeepLException If any error occurs while communicating with the DeepL API.
    */
   public Usage getUsage() throws DeepLException, InterruptedException {
-    HttpResponse response = httpClientWrapper.sendRequestWithBackoff("/v2/usage");
+    HttpResponse response = httpClientWrapper.sendGetRequestWithBackoff("/v2/usage");
     checkResponse(response, false, false);
     return jsonParser.parseUsage(response.getBody());
   }