fix(gofeatureflag): Added Locale.ENGLISH to SimpleDateFormat for parsing the Last-Modified HTTP header (#1626)

Signed-off-by: YuXiaoFeng <43255432@qq.com>
Co-authored-by: Thomas Poignant <thomas.poignant@gofeatureflag.org>

Author: kuaikuai

providers/go-feature-flag/src/main/java/dev/openfeature/contrib/providers/gofeatureflag/api/GoFeatureFlagApi.java

@@ -35,6 +35,7 @@
 import java.util.Collections;
 import java.util.Date;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import lombok.Builder;
 import lombok.extern.slf4j.Slf4j;
@@ -284,7 +285,8 @@ private Date extractLastUpdatedFromHeaders(final HttpResponse<String> response)
             String headerValue = response.headers()
                     .firstValue(Const.HTTP_HEADER_LAST_MODIFIED)
                     .orElse(null);
-            SimpleDateFormat lastModifiedHeaderFormatter = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss zzz");
+            SimpleDateFormat lastModifiedHeaderFormatter =
+                    new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss zzz", Locale.ENGLISH);
             return headerValue != null ? lastModifiedHeaderFormatter.parse(headerValue) : null;
         } catch (Exception e) {
             log.debug("Error parsing Last-Modified header: {}", e.getMessage());