Make sure the port forwarding protocol is always lowercase #6131

Job	Run time
Colima (v0.6.5)	7m 11s
Integration tests	3m 32s
Integration tests (on Linux) (alpine.yaml)	6m 29s
Integration tests (on Linux) (debian.yaml)	6m 21s
Lints	1m 53s
Integration tests (on Linux) (fedora.yaml)	6m 40s
Integration tests (on Linux) (opensuse.yaml)	7m 11s
Spell check	8s
Integration tests (on Linux) (docker.yaml)	7m 12s
Integration tests (on Linux) (../hack/test-templates/alpine-iso-9p-writable.yaml)	5m 38s
Unit tests (1.22.x)	38s
Integration tests (on Linux) (../hack/test-templates/net-user-v2.yaml)	7m 26s
Unit tests (1.23.x)	47s
Integration tests (on Linux) (../hack/test-templates/test-misc.yaml)	19m 45s
Upgrade test (v0.15.1)	9m 54s
VMNet test	10m 4s
vz (default.yaml)	10m 14s
Windows tests	3m 39s
vz (fedora.yaml)	11m 42s
	2h 6m 24s

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