config.tf: Bump KVO to v1.8.4-kvo.3
config.tf: Bump KVO to v1.8.4-kvo.3

This is to make upgrade test pass as it's trying to upgrade from
179-3, which the current kvo in the config.tf doesn't know about.

metral/tectonic-installer,alexsomesan/tectonic-installer,metral/tectonic-installer,justaugustus/tectonic-installer,zbwright/tectonic-installer,squat/tectonic-installer,zbwright/tectonic-installer,zbwright/tectonic-installer,squat/tectonic-installer,lander2k2/tectonic-installer,kalmog/tectonic-installer,zbwright/tectonic-installer,kyoto/tectonic-installer,lander2k2/tectonic-installer,cpanato/tectonic-installer,kyoto/tectonic-installer,mrwacky42/tectonic-installer,mrwacky42/tectonic-installer,hhoover/tectonic-installer,kyoto/tectonic-installer,kyoto/tectonic-installer,cpanato/tectonic-installer,cpanato/tectonic-installer,metral/tectonic-installer,kyoto/tectonic-installer,alexsomesan/tectonic-installer,metral/tectonic-installer,justaugustus/tectonic-installer,mrwacky42/tectonic-installer,hhoover/tectonic-installer,kalmog/tectonic-installer,hhoover/tectonic-installer,mrwacky42/tectonic-installer,hhoover/tectonic-installer,zbwright/tectonic-installer,alexsomesan/tectonic-installer,alexsomesan/tectonic-installer,squat/tectonic-installer,justaugustus/tectonic-installer,metral/tectonic-installer,justaugustus/tectonic-installer,derekhiggins/installer,squat/tectonic-installer,mrwacky42/tectonic-installer,alexsomesan/tectonic-installer,justaugustus/tectonic-installer,derekhiggins/installer,lander2k2/tectonic-installer,hhoover/tectonic-installer,lander2k2/tectonic-installer,kalmog/tectonic-installer,cpanato/tectonic-installer