Update signing.asc

Author: rmtheis

book/07-git-tools/sections/signing.asc

@@ -36,7 +36,7 @@ Now Git will use your key by default to sign tags and commits if you want.
 
 ==== Signing Tags
 
-If you have a GPG private key setup, you can now use it to sign new tags.
+If you have a GPG private key set up, you can now use it to sign new tags.
 All you have to do is use `-s` instead of `-a`:
 
 [source,console]