[WIP] Enable upgrading only specified repos #74

Job	Run time
populate-targets	3s
newt dump (bleprph-nrf52840pdk, ubuntu-latest)	29s
newt dump (bleprph-nrf52840pdk, windows-latest)	1m 24s
newt dump (bleprph-nrf52840pdk, macos-latest)	45s
newt dump (boot-nrf52dk, ubuntu-latest)	32s
newt dump (boot-nrf52dk, windows-latest)	1m 45s
newt dump (boot-nrf52dk, macos-latest)	40s
newt dump (btshell-nrf52840pdk, ubuntu-latest)	29s
newt dump (btshell-nrf52840pdk, windows-latest)	2m 48s
newt dump (btshell-nrf52840pdk, macos-latest)	2m 31s
newt dump (btshell-nrf52dk, ubuntu-latest)	30s
newt dump (btshell-nrf52dk, windows-latest)	1m 45s
newt dump (btshell-nrf52dk, macos-latest)	37s
newt dump (my_blinky_sim, ubuntu-latest)	27s
newt dump (my_blinky_sim, windows-latest)	1m 5s
newt dump (my_blinky_sim, macos-latest)	33s
	16m 23s

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