Update secrets analyzer dependencies to latest versions

SAST's secrets analyzer uses two upstream dependencies to do its work.

• gitleaks
• Trufflehog

We're currently shipping gitleaks v1.24.0. However, v3.3.0 shipped Feb 1, 2020. We need to update to the latest and greatest.

We're also shipping trufflehog v2.0.98. However, v2.0.99 shipped 6 May, 2019. We need to also update this dependency.

Addressing breaking changes

New versions of gitleaks remove one of the CLI options we rely on (see #12948 (comment 287252726)), so we will need to address the incompatibility issue with some additional logic to convert the passed ENV variable into a configuration option within gitleaks.toml