Upgrade Go version to 1.26.3

[github-actions]

Upgrade Go version to 1.26.3:
https://go.dev/doc/devel/release

• Set PR as "Ready for review"
• Check CI
• Submit PR review

[github-actions]

Overview

Image reference	score-k8s:latest	score-k8s:latest
- digest	a2146c9af719	e91cf9c5a5a9
- tag	latest	latest
- provenance	5134c57	f46b903
- vulnerabilities
- platform	linux/amd64	linux/amd64
- size	8.2 MB	8.2 MB (+9.9 kB)
- packages	64	64

Policies (1 improved, 0 worsened)

Policy Name	score-k8s:latest	score-k8s:latest	Change	Standing
Default non-root user	✅	✅		No Change
No AGPL v3 licenses	✅	✅		No Change
No fixable critical or high vulnerabilities	⚠️ 1	✅	-1	Improved
No high-profile vulnerabilities	✅	✅		No Change
No outdated base images	✅	✅		No Change
No unapproved base images	✅	✅		No Change
Supply chain attestations	✅	✅		No Change
Valid Docker Hardened Image (DHI) or DHI base image	⚠️ 2	⚠️ 2		No Change

Packages and Vulnerabilities (13 package changes and 1 vulnerability changes)

• ♾️ 13 packages changed
• 51 packages unchanged

• ✔️ 1 vulnerabilities removed

Changes for packages of type golang (13 changes)

	Package	Version score-k8s:latest	Version score-k8s:latest
♾️	github.com/fxamacker/cbor/v2	2.9.1	2.9.2
♾️	github.com/masterminds/semver/v3	3.4.0	3.5.0
♾️	github.com/mattn/go-isatty	0.0.21	0.0.22
♾️	github.com/olekukonko/errors	1.2.0	1.3.0
♾️	github.com/score-spec/score-k8s	0.0.0-20260511222645-5134c57cdcc8+dirty	0.0.0-20260511222717-f46b9031129c+dirty
♾️	github.com/tidwall/gjson	1.18.0	1.19.0
♾️	golang.org/x/crypto	0.49.0	0.51.0
♾️	golang.org/x/net	0.52.0	0.54.0
		Removed vulnerabilities (1):
♾️	golang.org/x/sys	0.43.0	0.44.0
♾️	golang.org/x/text	0.35.0	0.37.0
♾️	k8s.io/kube-openapi	0.0.0-20260330154417-16be699c7b31	0.0.0-20260511211612-da4e56fe5676
♾️	k8s.io/utils	0.0.0-20260319190234-28399d86e0b5	0.0.0-20260507154919-ff6756f316d2
♾️	sigs.k8s.io/structured-merge-diff/v6	6.3.2	6.4.0

[mathieu-benoit]

LGTM