Upgrading setuptools to 51.0.0

Some newer packages, in requirements.txt,  use the Metadata
version format available in 51.0.0.

Docs: https://setuptools.readthedocs.io/en/latest/userguide/declarative_config.html#metadata



Change-Id: I2a7c22c2fa42e7111aed462b81f5be9040d0d7f9
Signed-off-by: sousaedu <eduardo.sousa@canonical.com>