fix: allow cors preflight requests

src/main/java/com/litoralregas/openvpn/security/ApiKeyFilter.java

@@ -33,6 +33,11 @@ public class ApiKeyFilter extends OncePerRequestFilter {
             return;
         }
 
+        if ("OPTIONS".equalsIgnoreCase(request.getMethod())) {
+            filterChain.doFilter(request, response);
+            return;
+        }
+
         String apiKey = request.getHeader(HEADER);
 
         if (apiKey == null || !apiKey.equals(properties.getApiKey())) {