You can trust (in time), but you can't blindly upgrade. Vendor or choose to "lock" with a cryptographic hash over the files your build depends on. You then need to rebuild that trust when you upgrade (wait until everyone else does; read the diffs yourself).

There is something to be said for the Go proverb "a little copying is better than a little dependency", as well. If you want a simple function from a complicated library, you can probably copy it into your own codebase.