Add functions to get api package metadata path

Signed-off-by: Jono Yang <jyang@nexb.com>

Author: JonoYang

aboutcode/federated/__init__.py

@@ -383,6 +383,7 @@
 
 KIND_PURLS_FILENAME = "purls.yml"
 KIND_VULNERABILITIES_FILENAME = "vulnerabilities.yml"
+KIND_API_PACKAGE_METADATA_FILENAME = "api_package_metadata.yml"
 
 
 def get_package_purls_yml_file_path(purl: Union[PackageURL, str]):
@@ -399,6 +400,13 @@ def get_package_vulnerabilities_yml_file_path(purl: Union[PackageURL, str]):
     return get_package_base_dir(purl) / KIND_VULNERABILITIES_FILENAME
 
 
+def get_api_package_metadata_file_path(purl: Union[PackageURL, str]):
+    """
+    Return the path to a Package api_package_metadata.yml YAML for a purl.
+    """
+    return get_package_base_dir(purl) / KIND_API_PACKAGE_METADATA_FILENAME
+
+
 def get_package_base_dir(purl: Union[PackageURL, str]):
     """
     Return the base path to a Package directory (ignoring version) for a purl