Fix search path for templates

[fcurella]

When using a custom config file (via ``--config-file`), the config file name is included in the directory path passed to the template loader.

For example, given the following config:

template:
  # `template.package` and `template.directory` can be use to list the Python
  # packages and / or directories to search for templates. Can either be a single
  # item or an array of items.
  directory: [.conventional/templates]

  # The name of the template to load
  name: changelog.md

  # If `True`, unparsed commits will be included when rendering the template.
  include-unparsed: false

  # Configuration specific to the template defined by `template.package` + `template.name`
  # (see https://jinja.palletsprojects.com/en/2.11.x/api/#jinja2.PackageLoader) in this
  # case the configuration is for the `changelog.md` template.
  config:
    # Mapping of types (parsed from git commits) to the headings to use when listing them
    # in the changelog. If a type is missing from this list, commits using that type will
    # not be added to the changelog.
    type-headings:
      feat: Features
      fix: Fixes

by calling:

conventional --config-file conventional.yaml template

conventional will look into <CWD>/conventional.yaml/.conventional/templates, when it should look into <CWD>/.conventional/templates instead

[Roguelazer]

any chance of getting this landed? it's kind of silly...