BUILD/MEDIUM: go: upgrade to go 1.26 and a new linter #1272

Job	Run time
generate-models	1m 34s
generate-specification	48s
HAProxy check commit message	0s
go mod tidy	-1s
lint-spec	-1s
license-check	-1s
golangci-lint	-1s
Build	-1s
Test equal	0s
e2e on HAProxy	0s
Tests	0s
	2m 17s

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