This function generates PMtiles for coherent network GeoJSON file using the Tippecanoe tool.
     
    
    Usage
    create_coherent_network_PMtiles(folder_path, city_filename, cohesive_network)
 
    
    Arguments
- folder_path
- The directory path where the files will be saved. 
- city_filename
- The base name for the output files, in this case using city name. 
- cohesive_network
- An sf object representing the cohesive network. 
 
    
    Value
    The output from the Tippecanoe command as a character vector.