Upgrade Go to 1.25.9 to fix CVE-2026-32280, CVE-2026-32281, CVE-2026-32283 (#979)

* Initial plan

* Upgrade Go to 1.25.9 to fix CVE-2026-32280, CVE-2026-32281, CVE-2026-32283

Update go.mod and Dockerfile.release to use Go 1.25.9, which includes
fixes for CVE-2026-32280, CVE-2026-32281, and CVE-2026-32283 (HIGH).

Agent-Logs-Url: https://github.com/databus23/helm-diff/sessions/990aa998-c0a8-4420-9578-6624fec26948

Co-authored-by: yxxhero <11087727+yxxhero@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: yxxhero <11087727+yxxhero@users.noreply.github.com>

Author: Copilot

Dockerfile.release

@@ -1,4 +1,4 @@
-FROM golang:1.25
+FROM golang:1.25.9
 
 # See https://github.com/cli/cli/blob/trunk/docs/install_linux.md#debian-ubuntu-linux-raspberry-pi-os-apt
 # for the latest gh install instructions when the below didn't work

go.mod

@@ -1,6 +1,6 @@
 module github.com/databus23/helm-diff/v3
 
-go 1.25.7
+go 1.25.9
 
 require (
 	github.com/Masterminds/semver/v3 v3.4.0