fix: Vulnerability fix for starkbank-ecdsa 2.2.0 dependency

[ranjanprasad1996]

Fixes

As part of the quay.io vulnerability report, it is reported that the sendgrid-python==6.11.0 package has a vulnerability (GHSA-9wx7-jrvc-28mm) reported for dependency starkbank-ecdsa==2.2.0 which is the latest version available from 2022 (The starbank repository no longer seems to be maintained).

This PR solves replaces the outdated starbank-ecdsa library (https://github.com/starkbank/ecdsa-python) with an actively mainained library ecdsa (https://github.com/tlsfuzzer/python-ecdsa).

Checklist

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