crowdin: Use separate keys for pushing to znc and znc-jenkins

.ci/Jenkinsfile.crowdin

@@ -69,14 +69,20 @@ timestamps {
                 }
                 sh "git remote add my github.com:${my_user}/${my_repo}.git"
                 // TODO simplify when https://issues.jenkins-ci.org/browse/JENKINS-28335 is fixed
+                if (!pr_mode) {
+                  withCredentials([sshUserPrivateKey(credentialsId: 'baf2df74-935d-40e5-b20f-076e92fa3e9f', keyFileVariable: 'GITHUB_KEY')]) {
+                    sh 'echo ssh -i $GITHUB_KEY -l git -o StrictHostKeyChecking=no \\"\\$@\\" > run_ssh.sh'
+                    sh 'chmod +x run_ssh.sh'
+                    withEnv(['GIT_SSH=run_ssh.sh']) {
+                      sh "git push upstream HEAD:refs/heads/${upstream_branch}"
+                    }
+                  }
+                  return
+                }
                 withCredentials([sshUserPrivateKey(credentialsId: '6ef10f80-20dc-4661-af45-52a6e1e15749', keyFileVariable: 'GITHUB_KEY')]) {
                   sh 'echo ssh -i $GITHUB_KEY -l git -o StrictHostKeyChecking=no \\"\\$@\\" > run_ssh.sh'
                   sh 'chmod +x run_ssh.sh'
                   withEnv(['GIT_SSH=run_ssh.sh']) {
-                    if (!pr_mode) {
-                      sh "git push upstream HEAD:refs/heads/${upstream_branch}"
-                      return
-                    }
                     sh "git push my HEAD:refs/heads/${my_branch} -f"
                   }
                 }