openforcefield/openforcefield: 0.8.2 Bugfix release

0.8.2 Bugfix release For the complete release notes, please see our documentation PR #786: Fixes Issue #785 where RDKitToolkitWrapper would sometimes expect stereochemistry to be defined for non-stereogenic bonds when loading from SDF. PR #786: Fixes an issue where using the Molecule copy constructor (newmol = Molecule(oldmol)) would result in the copy sharing the same .properties dict as the original (as in, changes to the .properties dict of the copy would be reflected in the original). PR #789: Fixes a regression noted in Issue #788 where creating vdWHandler.vdWType or setting sigma or rmin_half using quantities represented as strings resulted in an error. For help getting the OpenFF Toolkit running, see our installation instructions. Please report bugs, request features, or ask questions through our issue tracker. Please note that there may still be some changes to the API prior to a stable 1.0.0 release