fix giphy borderradius

lib/src/giphy_attachment.dart

@@ -79,6 +79,11 @@ class GiphyAttachment extends StatelessWidget {
                           );
                         }));
                       },
+                      child: ClipRRect(
+                        borderRadius: BorderRadius.only(
+                          topLeft: Radius.circular(8),
+                          topRight: Radius.circular(8),
+                        ),
                         child: CachedNetworkImage(
                           height: size?.height,
                           width: size?.width,
@@ -102,6 +107,7 @@ class GiphyAttachment extends StatelessWidget {
                         ),
                       ),
                     ),
+                  ),
                   Positioned(
                     bottom: 16,
                     left: 16,