Replace deprecated `input_files.append` with dict access.

analysis/framework.py

@@ -223,7 +223,7 @@ class HTCondorWorkflow(law.contrib.htcondor.HTCondorWorkflow, HTCondorRemoteStor
         os.system('tar --exclude=luigi/.git --exclude={}/SteerModify.str -czf analysis.tar.gz analysis luigi.cfg law.cfg luigi law six enum34-1.1.10 python-dateutil-2.8.2 {} {}'.format(self.steer_dir, self.base_runcard, self.steer_dir))
         os.chdir(prevdir)
 
-        config.input_files.append(law.util.rel_path(__file__, '../analysis.tar.gz'))
+        config.input_files['analysis'] = law.util.rel_path(__file__, '../analysis.tar.gz')
         return config
 
     def htcondor_use_local_scheduler(self):