Fix readme typo

Author: Kimahriman

README.md

@@ -50,7 +50,7 @@ yum install krb5-libs
 brew install krb5
 ```
 
-#### WIndows
+#### Windows
 Download and install the Microsoft Kerberos package from https://web.mit.edu/kerberos/dist/
 
 Copy the `<INSTALL FOLDER>\MIT\Kerberos\bin\gssapi64.dll` file to a folder in %PATH% and change the name to `gssapi_krb5.dll`