bpo-30119: fix ftplib.FTP.putline() to throw an error for a illegal command (#1214)

diff --git a/Lib/ftplib.py b/Lib/ftplib.py
index 8f36f53..a02e595 100644
--- a/Lib/ftplib.py
+++ b/Lib/ftplib.py
@@ -186,6 +186,8 @@
 
     # Internal: send one line to the server, appending CRLF
     def putline(self, line):
+        if '\r' in line or '\n' in line:
+            raise ValueError('an illegal newline character should not be contained')
         line = line + CRLF
         if self.debugging > 1:
             print('*put*', self.sanitize(line))