shot at preventing resource leak

So far this diverges from the rest of the codebase locations but
let's see if it passes at least.

Author: pevogam

guibot/finder.py

@@ -605,8 +605,11 @@ def find(self, needle: "Image", haystack: "Image") -> "list[Match]":
         # TODO: Use in-memory conversion
         with NamedTemporaryFile(prefix="guibot", suffix=".png") as f:
             filename = f.name
-        haystack.save(filename)
-        autopy_screenshot = bitmap.Bitmap.open(filename)
+        try:
+            haystack.save(filename)
+            autopy_screenshot = bitmap.Bitmap.open(filename)
+        finally:
+            os.unlink(filename)
 
         autopy_tolerance = 1.0 - self.params["find"]["similarity"].value
         log.debug(