Upgrade Go to 1.26.2 to fix stdlib CVEs (v6.2.2)

[reinkrul]

Summary

• Upgrade Go from 1.26.1 to 1.26.2 in go.mod and Dockerfile
• Add release notes for v6.2.2

Fixes the following Go stdlib vulnerabilities:

Advisory	Package	Description
GO-2026-4865	html/template	XSS via incorrect JS template literal escaping
GO-2026-4866	crypto/x509	Auth bypass via excluded DNS name constraints not applied to wildcard SANs
GO-2026-4869	archive/tar	DoS via unbounded memory allocation in tar reader
GO-2026-4870	crypto/tls	DoS via TLS 1.3 connection deadlock on multiple KeyUpdate messages
GO-2026-4946	crypto/x509	DoS via inefficient policy validation with many policy mappings

Test plan

• CI passes (govulncheck should report no stdlib vulnerabilities)
• Docker image builds with golang:1.26.2-alpine

🤖 Generated with Claude Code

[qltysh]

Coverage Impact

⬆️ Merging this pull request will increase total coverage on V6.2 by 0.01%.

🚦 See full report on Qlty Cloud »

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