fix: mcp/python-google-adk-trusted-auth/requirements.txt to reduce vulnerabilities

The following vulnerabilities are fixed by pinning transitive dependencies:
- https://snyk.io/vuln/SNYK-PYTHON-PYGMENTS-15746419

Author: snyk-io[bot]

mcp/python-google-adk-trusted-auth/requirements.txt

@@ -5,3 +5,4 @@ aiohttp>=3.8.0
 rich>=13.0.0
 Flask>=2.2.5
 requests>=2.32.4
+pygments>=2.20.0 # not directly required, pinned by Snyk to avoid a vulnerability