Bump Python 3.13 and 3.14 support packages (#61)

Author: freakboy3742

{{ cookiecutter.format }}/briefcase.toml

@@ -12,8 +12,8 @@ support_path = "Support"
     "3.10": "support_revision = 12",
     "3.11": "support_revision = 7",
     "3.12": "support_revision = 7",
-    "3.13": "support_revision = 10",
-    "3.14": "support_revision = 6",
+    "3.13": "support_revision = 12",
+    "3.14": "support_revision = 8",
 }.get(cookiecutter.python_version|py_tag, "") }}
 
 icon.20 = "{{ cookiecutter.class_name }}/Images.xcassets/AppIcon.appiconset/icon-20.png"