Fix build args input name, and remove unnsupported inputs. (#4)

action.yml

@@ -24,12 +24,9 @@ inputs:
   tar_file:
     description: "Tarball name to save the image, the file is saved into Workspace by default."
     required: false
-  build-args:
+  build_args:
     description: 'Space separated list of extra build-args (build-time variables)'
     required: false
-  kaniko-args:
-    description: 'Extra arguments for the CLI command'
-    required: false
 runs:
   using: 'docker'
   image: 'Dockerfile'