Fix compatibility issues with older python versions

Signed-off-by: Marcus Burghardt <[email protected]>

ssg/variables.py

@@ -19,7 +19,7 @@
 _var_files_cache = {}
 
 
-def get_variable_files_in_folder(content_dir: str, subfolder: str) -> list[str]:
+def get_variable_files_in_folder(content_dir: str, subfolder: str) -> list:
     """
     Retrieve a list of variable files within a specified folder in the project.
 
@@ -36,7 +36,7 @@ def get_variable_files_in_folder(content_dir: str, subfolder: str) -> list[str]:
     return glob.glob(pattern, recursive=True)
 
 
-def get_variable_files(content_dir: str) -> list[str]:
+def get_variable_files(content_dir: str) -> list:
     """
     Retrieves all variable files from the specified content root directory.