CI: typo checker should ignore `go.sum`

[AkihiroSuda]

https://github.com/lima-vm/lima/actions/runs/11466623611/job/31907690858?pr=2782

./go.sum:653: BU ==> BY, BE, BUT, BUG, BUN, BUD, BUY, BUM

Hit in:

• [POC, DNM] Expose socks proxy (per user-v2 net, not per instance) #2782