Handle difficult filenames.

- Involving unix filenames and unicode surrogates...
- Seen in instagram's cinder repo.

eris/worker.py

@@ -37,7 +37,7 @@ class Worker:
     async def run_tool(self, path, tool):
         while True:
             self.process.stdin.write(
-                f"{tool.__qualname__}\n{path}\n".encode("utf-8"))
+                f"{tool.__qualname__}\n{path}\n".encode("utf-8", "surrogatepass"))
             data = await self.process.stdout.readline()
             if data == b"":
                 await self.create_process()