Modin 0.7.1 release notes

In this release we focused on improving testing infrastructure and fixing outstanding bugs. One particular longstanding bug with the Dask runtime, related to serialization, was fixed (modin-project#1096). This revealed an oppourtinity for more optimization when it comes to serialization within the repository.

Bugfixes + Pandas Concordance (🐛 + 🐼)
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* Fix loc when column mask is boolean and no rows are masked (modin-project#1039)
* Fix opening a file from s3 when S is capitalized (modin-project#1045)
* Fix pd.to_datetime when using a Series object. (modin-project#1048)
* Fix issue with Dask engine where users were not able to use Da (modin-project#1050)
* Fix `as_index=False` for `DataFrame.groupby` (modin-project#1041)
* Fix ingesting parquet files that are coming from HDFS (modin-project#1074)
* fixed bug where .to_frame(name) ignored name; added parity wit (modin-project#1075)
* Fix column indexing when 2 or more columns have same name (modin-project#1077)
* Fix Series.__getitem__ to accept a callable as key (modin-project#1084)
* bugfix - sometimes df.loc[s] applies to columns instead of rows (modin-project#1088)
* df.rename works with 'mapper' and 'axis' params (modin-project#1057)
* Fix case where apply a Series across the columns threw error (modin-project#1092)
* Fix Dask Serialization issue (modin-project#1096)

New Functionality ✨
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* Add r operators to Series (modin-project#1086)

Code Quality + Testing 💯
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* Update Test infrastructure to use testmon when possible (modin-project#1036)
* Re-enable testmon force selection (modin-project#1040)
* Update master to track coverage again (modin-project#1052)
* Update test for groupby and clean up groupby edge cases (modin-project#1055)
* Change Error to warning for pandas version pin (modin-project#1072)
* Upload coverage correctly from merged PRs (modin-project#1076)

Documentation 📃
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* Update Installation Documentation (modin-project#1066)
* Documentation updates (modin-project#1097)
* Add documentation for signed-off-by policy (modin-project#1098)

Dependencies 🔗
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* Unpin tables version for CI to support Ubuntu 19+ (modin-project#1080)
* Pin msgpack < 1.0 (modin-project#1090)

Contributors this release
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The following users contributed code to Modin since the last release.

@elonp (First time contributor) ⭐️
@KevOBrien (First time contributor) ⭐️
@devin-petersohn (Maintainer)

🎉🎉 Thank you! 🎉🎉

Bump version to 0.7.0 (modin-project#1029)

Bump version to 0.6.3 (modin-project#871)

Bump version to 0.6.2 (modin-project#834)

Bump version to 0.6.1 (modin-project#805)

Version bump/0.6.0 (modin-project#776)

* Bump version to 0.6.0

* Fix readme badge

Release 0.5.4 (modin-project#740)

Bump to 0.5.3 (modin-project#695)

Bump to 0.5.2 (modin-project#645)

Bump version to 0.5.1 (modin-project#640)