How to make a wolf angry at a nearby player

Who a wolf is angry at is not saved in its NBT. I've created this bug report for it now: https://bugs.mojang.com/browse/MC-155036

But you can still do what you want to do, because wolves really don't like snowball fights.
Let's say the player who should be attacked has the tag "attackMe", just to have something to differentiate them. Then you can summon a snowball above the wolf and make that snowball pretend to have been thrown by that player:

execute at @e[type=wolf] run summon snowball ~ ~2 ~
execute at @e[type=wolf] run data modify entity @e[type=snowball,sort=nearest,limit=1] owner.L set from entity @p[tag=attackMe] UUIDLeast
execute at @e[type=wolf] run data modify entity @e[type=snowball,sort=nearest,limit=1] owner.M set from entity @p[tag=attackMe] UUIDMost

Of course you'll probably narrow the selector @e[type=wolf] further, currently this system makes every wolf in the loaded area angry at you.