Release v2.7.0

• Added: strict argument to audeer.load_configuration().
  With strict=True user configurations
  and environment variables
  may only contain keys and types of the default configuration file
• Added: expand_vars argument to audeer.path()
  to expand environment variables
• Added: support for Python 3.15
• Changed: audeer.load_configuration() is marked as experimental
  and might have breaking changes in a future release
• Changed: audeer.load_configuration()
  deep-merges an environment section variable
  like a user configuration,
  instead of replacing it.
  Its values are only type-checked
  if strict is True
• Changed: audeer.load_configuration()
  raises a ValueError
  if a user configuration,
  or an environment section variable,
  sets a section of the default configuration file to a value,
  or a value to a section
• Changed: audeer.load_configuration()
  now always converts an integer to a float
  if the default value is a float
• Removed: dict as a supported type
  in the types argument of audeer.load_configuration(),
  use an empty section {} as default value instead
• Removed: support for Python 3.10