Fix the new CI script

.ci/Jenkinsfile.crowdin

@@ -55,7 +55,7 @@ timestamps {
                   def contributors = httpRequest consoleLogResponseBody: true, customHeaders: headers, url: "https://crowdin.com/api/v2/projects/289533/members?limit=500"
                   writeFile file: 'contributors.tmp', text: contributors.content
                 }
-                sh '.ci/crowdin-contributors.py < contributors.tmp'
+                sh 'test -x .ci/crowdin-contributors.py && .ci/crowdin-contributors.py < contributors.tmp'
                 sh 'rm contributors.tmp'
               }
               stage("Push ${upstream_branch}") {

.ci/crowdin-contributors.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 import json
 import sys