chore: release 2.77.0
Version bump and changelog for the `latch image upload` reliability series.
2.77.0 rather than 2.76.11: `--pull` flips a default, so a CI job that runs
`latch image upload some/ref` without a local build goes from succeeding to
exiting 1. `get_credentials` also gains a required keyword argument. Both are
breaking for existing callers, which semver puts in a minor bump rather than a
patch. Provisional - happy to be argued down to a patch if the old pull
behaviour is considered a bug rather than a feature.
