MINOR: Add 4 new tunable keywords for HAProxy 3.4 #1173

Job	Run time
generate-models	1m 35s
generate-specification	1m 0s
HAProxy check commit message	0s
lint-spec	0s
go mod tidy	0s
Build	0s
golangci-lint	0s
license-check	0s
Tests	0s
Test equal	0s
e2e on HAProxy	0s
	2m 35s

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