feat(backend): add more supported image types

backend/src/main/java/io/papermc/hangarauth/config/WebConfig.java

@@ -52,6 +52,19 @@ public ByteArrayHttpMessageConverter byteArrayHttpMessageConverter() {
         return converter;
     }
 
+    private List<MediaType> getSupportedMediaTypes() {
+        return List.of(
+            MediaType.IMAGE_JPEG,
+            MediaType.IMAGE_PNG,
+            MediaType.APPLICATION_OCTET_STREAM,
+            MediaType.IMAGE_GIF,
+            new MediaType("image", "svg+xml"),
+            new MediaType("image", "webp"),
+            new MediaType("image", "apng"),
+            new MediaType("image", "avif")
+        );
+    }
+
     @Bean
     public Filter identifyFilter() {
         return new OncePerRequestFilter() {
@@ -71,16 +84,6 @@ public FilterRegistrationBean<ShallowEtagHeaderFilter> shallowEtagHeaderFilterFi
         return bean;
     }
 
-    private List<MediaType> getSupportedMediaTypes() {
-        return List.of(
-            MediaType.IMAGE_JPEG,
-            MediaType.IMAGE_PNG,
-            MediaType.APPLICATION_OCTET_STREAM,
-            new MediaType("image", "svg+xml"),
-            new MediaType("image", "webp")
-        );
-    }
-
     @Override
     public void addCorsMappings(final CorsRegistry registry) {
         final String[] avatarCorsOrigins = new String[this.generalConfig.allowedOrigins().length + 1];