Fix plugin loading compatibility with Python 3.12 and newer.
Replace the removed imp module with importlib.util for loading plugins
from file paths. Register dynamically loaded modules in sys.modules
and remove them if execution fails.
--- ../boto/plugin.py	2026-10-18 00:24:16.094462480 +0300
+++ ../boto/plugin.py	2026-10-18 00:25:37.901980912 +0300
@@ -37,8 +37,9 @@
 """
 
 import glob
-import imp
+import importlib.util
 import os.path
+import sys
 
 
 class Plugin(object):
@@ -70,12 +71,18 @@
     (path, name) = os.path.split(filename)
     (name, ext) = os.path.splitext(name)
 
-    (file, filename, data) = imp.find_module(name, [path])
+    spec = importlib.util.spec_from_file_location(name, filename)
+    if spec is None or spec.loader is None:
+        raise ImportError('Unable to load plugin: %s' % filename)
+
+    module = importlib.util.module_from_spec(spec)
+    sys.modules[name] = module
     try:
-        return imp.load_module(name, file, filename, data)
-    finally:
-        if file:
-            file.close()
+        spec.loader.exec_module(module)
+    except BaseException:
+        sys.modules.pop(name, None)
+        raise
+    return module
 
 _plugin_loaded = False