release notes for 0.27.0 (filecoin-project#96)

add changelog and changelog generator (filecoin-project#95)

consume new abi.SealVerifyInfo structure (filecoin-project#89)

consume new abi.SealVerifyInfo structure (filecoin-project#89)

Merge pull request filecoin-project#84 from filecoin-project/bugs/kee…

…palive-in-wrong-spot

don't let Go garbage collect FD until FFI call returns

fix: error if there is already a logger

The file logger needs to be initialized as the first action when calling the
FFI. If there was already any logger initialized, return an error when trying
to initialize the file logger.

add winning PoSt for 64 GiB (filecoin-project#93)

Merge pull request filecoin-project#91 from filecoin-project/update-d…

…eps-revisited

Update deps revisited

Merge pull request filecoin-project#91 from filecoin-project/update-d…

…eps-revisited

Update deps revisited

newest upstream (filecoin-project#88)