[deployment/chef] Fix custom variables handling on Windows #13370

Job	Run time
setup-environment	1m 31s
generate-metrics	5m 57s
gofmt	7m 23s
tidy	2m 11s
coverage	12m 21s
lint	17m 23s
test	17m 13s
cross-compile (binaries-darwin_amd64)	5m 22s
cross-compile (binaries-darwin_arm64)	5m 26s
cross-compile (binaries-linux_amd64)	5m 24s
cross-compile (binaries-linux_arm64)	5m 17s
cross-compile (binaries-windows_amd64)	5m 21s
cross-compile (binaries-linux_ppc64le)	5m 21s
	1h 36m 10s

Provide feedback