www/nginx-prometheus-exporter: Update 1.4.1 => 1.4.2

Changelog:
https://github.com/nginx/nginx-prometheus-exporter/releases/tag/v1.4.2

Included security updates - dependencies bumped.

PR: 286438
Security: https://pkg.go.dev/vuln/GO-2025-3503
Security: https://pkg.go.dev/vuln/GO-2025-3488
Security: https://pkg.go.dev/vuln/GO-2025-3487
MFH: 2025Q2
(cherry picked from commit 19a37e4984afcc661bf1dde66a6c57532cb7f677)