Fixed "Prefix too short"

app/src/main/java/eu/faircode/email/AdapterMessage.java

@@ -1369,7 +1369,7 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
                             response.setMethod(Method.REPLY);
                             response.addEvent(ev);
 
-                            File ics = File.createTempFile(Long.toString(attachment.id), ".ics", context.getCacheDir());
+                            File ics = File.createTempFile("calendar", ".ics", context.getCacheDir());
                             response.write(ics);
 
                             return ics;

app/src/main/java/eu/faircode/email/FragmentCompose.java

@@ -1913,7 +1913,7 @@ public class FragmentCompose extends FragmentBase {
                         resized = rotated;
                     }
 
-                    File tmp = File.createTempFile(Long.toString(attachment.id), ".resized", context.getCacheDir());
+                    File tmp = File.createTempFile("image", ".resized", context.getCacheDir());
                     try (OutputStream out = new FileOutputStream(tmp)) {
                         resized.compress("image/jpeg".equals(attachment.type)
                                         ? Bitmap.CompressFormat.JPEG