fix/remove unsupported character (Chainlit#442)

Co-authored-by: Clément Sirieix <[email protected]>

backend/chainlit/secret.py

@@ -2,7 +2,7 @@
 import string
 
 # Using punctuation, without chars that can break in the cli (quotes, backslash, backtick...)
-chars = string.ascii_letters + string.digits + "$%*+,-./:<=>?@^_~"
+chars = string.ascii_letters + string.digits + "$%*+,-./:=>?@^_~"
 
 
 def random_secret(length: int = 64):