Replace deprecated ConfigParser readfp with read_file

ConfigParser's `readfp()` has been deprecated since Python 3.2 and removed
in Python 3.12.

Author: City-busz

src/sugar3/bundle/activitybundle.py

@@ -129,7 +129,7 @@ def __init__(self, path, translated=True):
 
     def _parse_info(self, info_file):
         cp = ConfigParser()
-        cp.readfp(info_file)
+        cp.read_file(info_file)
 
         section = 'Activity'
 
@@ -238,7 +238,7 @@ def _get_linfo_file(self):
     def _parse_linfo(self, linfo_file):
         cp = ConfigParser()
         try:
-            cp.readfp(linfo_file)
+            cp.read_file(linfo_file)
 
             section = 'Activity'
 

src/sugar3/bundle/contentbundle.py

@@ -67,7 +67,7 @@ def __init__(self, path):
 
     def _parse_info(self, info_file):
         cp = ConfigParser()
-        cp.readfp(info_file)
+        cp.read_file(info_file)
 
         section = 'Library'
 

src/sugar3/graphics/icon.py

@@ -208,7 +208,7 @@ def _get_attach_points(self, info, size_request):
                 try:
                     with open(icon_filename) as config_file:
                         cp = ConfigParser()
-                        cp.readfp(config_file)
+                        cp.read_file(config_file)
                         attach_points_str = cp.get('Icon Data', 'AttachPoints')
                         attach_points = attach_points_str.split(',')
                         attach_x = float(attach_points[0].strip()) / 1000