Center the bandit logo in readme
Minor nit change to center the logo in the readme for more visual
appeal.
-.. image:: https://github.com/PyCQA/bandit/blob/main/logo/logotype-sm.png
- :alt: Bandit
+.. raw:: html
+
+ <p align="center">
+ <img src="https://raw.githubusercontent.com/pycqa/bandit/main/logo/logotype-sm.png" alt="Bandit">
+ </p>
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