use npx for using marp

utils/ppt.py

@@ -2,7 +2,7 @@ import os
 
 def generate_ppt(markdown_source, output_name, chromium_path="./chrome_sandbox") -> None:
     # check for marp
-    if os.system("npx marp --version") != 0:
+    if os.system("npx -y @marp-team/marp-cli --version") != 0:
         raise Exception("Marp is not installed")
     
     # if user is root, then set CHROMIUM_PATH to chromium_path
@@ -14,4 +14,4 @@ def generate_ppt(markdown_source, output_name, chromium_path="./chrome_sandbox")
         raise Exception("Markdown source does not exist")
     
     # generate ppt
-    os.system(f"npx @marp-team/marp-cli {markdown_source} -o {output_name} --allow-local-files")
+    os.system(f"npx -y @marp-team/marp-cli {markdown_source} -o {output_name} --allow-local-files")