v0.7.0 Index statistics, TFRecord reader, improved tf.data reader

What's Changed

• [Doc] Add deep dive presentation to README by @eddyxu in #1167
• run format and clippy on latest rust by @wjones127 in #1171
• feat: expose index stats for debugging by @rok in #1097
• feat: add cleanup_old_versions method which will remove unreferenced old files by @westonpace in #1140
• [bench] Fix up rust benchmarks by @changhiskhan in #1176
• feat: add a background executor for Python by @wjones127 in #1172
• [python] Validate schema metadata by @changhiskhan in #1186
• use commit handler to find the latest version of a dataset by @chebbyChefNEQ in #1187
• Remove request dependency as it's only used for its re-export of http by @dnsco in #1189
• feat: add support for field metdata by @westonpace in #1173
• feat: parse TFRecords as Arrow data by @wjones127 in #1166
• feat: add function to cleanup partial writes by @wjones127 in #1182
• feat: tf.data support for binary, struct, and FixedShapeTensor by @wjones127 in #1191
• fix: make field name consistent by @wjones127 in #1192
• refactor: pass params by reference in from_uri_and_params method by @westonpace in #1194

Full Changelog: v0.6.5...v0.7.0