v0.2.5 Schema evolution, support merging with arrow Table

What's Changed

• [DOC] Fix notebook build by @eddyxu in #339
• [Python] lance.write_dataset takes pandas DataFrame by @eddyxu in #342
• [DOC] update readme docs to cater for import pathways from df/parquet by @jaichopra in #340
• [Python] Improve PyTorch dataset ergonomic by @eddyxu in #336
• [C++] Add columns from in-memory table by @eddyxu in #337
• [Python] append column with a in-memory Pyarrow Table by @eddyxu in #338
• [C++][Python] Add timestamp to each manifest version. by @eddyxu in #343

Full Changelog: v0.2.4...v0.2.5