update contributing.md - fix typo

Author: pushkyn

CONTRIBUTING.md

@@ -128,7 +128,7 @@ Please run your code through:
    # Clone your fork of the repo into the current directory
    git clone https://github.com/sendgrid/smtpapi-python
    # Navigate to the newly cloned directory
-   cd sendgrid-python
+   cd smtpapi-python
    # Assign the original repo to a remote called "upstream"
    git remote add upstream https://github.com/sendgrid/smtpapi-python
    ```