Treat .apk as a .tar file instead of erroring out

--- libabigail-1.7/src/abg-tools-utils.cc	2020-02-26 07:03:05.000000000 -0600
+++ libabigail-1.7/src/abg-tools-utils.cc	2020-04-17 08:10:18.899192507 -0500
@@ -1529,7 +1529,8 @@ guess_file_type(const string& file_path)
       || string_ends_with(file_path, ".tlz")
       || string_ends_with(file_path, ".tar.Z")
       || string_ends_with(file_path, ".taz")
-      || string_ends_with(file_path, ".tz"))
+      || string_ends_with(file_path, ".tz")
+      || string_ends_with(file_path, ".apk"))
     return FILE_TYPE_TAR;
 
   ifstream in(file_path.c_str(), ifstream::binary);