add *.cfg and workdir* masks to .gitignore
add *.cfg and workdir* masks to .gitignore

I have lots of them for testing.

hyz0906/syzkaller,xairy/syzkaller,xairy/syzkaller,google/syzkaller,dotweiba/syzkaller,hyz0906/syzkaller,hyz0906/syzkaller,xairy/syzkaller,xairy/syzkaller,zoulasc/syzkaller,dotweiba/syzkaller,google/syzkaller,google/syzkaller,google/syzkaller,xairy/syzkaller,zoulasc/syzkaller,xairy/syzkaller,google/syzkaller,zoulasc/syzkaller,google/syzkaller,xairy/syzkaller,dotweiba/syzkaller,google/syzkaller,hyz0906/syzkaller,hyz0906/syzkaller,zoulasc/syzkaller,dotweiba/syzkaller