autoblack: actions/checkout@v1 # Use v1, NOT v2 (#1796)

* autoblack: actions/checkout@v1  # Use v1, NOT v2

* fixup! Format Python code with psf/black push

Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>

ciphers/rot13.py

@@ -1,4 +1,4 @@
-def dencrypt(s: str, n: int=13):
+def dencrypt(s: str, n: int = 13):
     """
     https://en.wikipedia.org/wiki/ROT13
 
@@ -24,13 +24,14 @@ def main():
     s0 = input("Enter message: ")
 
     s1 = dencrypt(s0, 13)
-    print("Encryption:", s1)  
+    print("Encryption:", s1)
 
     s2 = dencrypt(s1, 13)
-    print("Decryption: ", s2)  
+    print("Decryption: ", s2)
 
 
 if __name__ == "__main__":
     import doctest
+
     doctest.testmod()
     main()