Update go module directive to v1.26.5 (release-2026-lts) (#10384)

Update go module directive to v1.26.5

| datasource     | package | from   | to     |
| -------------- | ------- | ------ | ------ |
| golang-version | go      | 1.26.4 | 1.26.5 |

Signed-off-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

go.mod

@@ -1,6 +1,6 @@
 module github.com/nginx/kubernetes-ingress
 
-go 1.26.4
+go 1.26.5
 
 require (
 	github.com/cert-manager/cert-manager v1.19.3