Update SPE plugin for v3 API (#963)

Author: lschr

imageio/config/plugins.py

@@ -126,6 +126,10 @@ def partial_legacy_plugin(request):
     class_name="TifffilePlugin",
     module_name="imageio.plugins.tifffile_v3",
 )
+known_plugins["SPE"] = PluginConfig(
+    name="spe", class_name="SpePlugin", module_name="imageio.plugins.spe"
+)
+
 
 # Legacy plugins
 # ==============
@@ -357,19 +361,6 @@ def partial_legacy_plugin(request):
     },
 )
 
-known_plugins["SPE"] = PluginConfig(
-    name="SPE",
-    class_name="SpeFormat",
-    module_name="imageio.plugins.spe",
-    is_legacy=True,
-    install_name="spe",
-    legacy_args={
-        "description": "SPE file format",
-        "extensions": ".spe",
-        "modes": "iIvV",
-    },
-)
-
 known_plugins["SWF"] = PluginConfig(
     name="SWF",
     class_name="SWFFormat",