chore(main): release 1.8.0

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1.8.0 (2024-05-31)

Features

• merge only generates a default index if both inputs already have an index (#733) (25d049c)
• Add +, - as unary ops, ^ binary op (#724) (968d825)
• Add GroupBy.size() to get number of rows in each group (#479) (1fca588)
• Add DataFrame ~ operator (#721) (354abc1)
• Add GeminiText 1.5 Preview models (#737) (56cbd3b)
• Add slot_millis and add stats to session object (#725) (72e9583)
• Adds bigframes.bigquery.array_to_string to convert array elements to delimited strings (#731) (f12c906)
• Allow functions decorated with bpd.remote_function() to execute locally (#704) (d850da6)
• Ensure "bigframes-api" label is always set on jobs, even if the API is unknown (#722) (1832778)
• Support ml.SimpleImputer in bigframes (#708) (4c4415f)
• Support type annotations to supply input and output types to bpd.remote_function() decorator (#717) (4a12e3c)
• Support type annotations with bpd.remote_function() and axis=1 (a preview feature) (#730) (e5a2992)

Bug Fixes

• Correct index labels in multiple aggregations for DataFrameGroupBy (#723) (6a78c89)
• Fix Null index assign series to column (#711) (ffb4b57)
• Set bpd.remote_function()s input_types and output_types default to None to allow omitting them when type annotations are present (#729) (0e25a3b)
• Warn and disable time travel for linked datasets (#712) (085fa9d)

Performance Improvements

• Optimize dataframe-series alignment on axis=1 (#732) (3d39221)

Documentation

• Add examples to DataFrameGroupBy and SeriesGroupBy (#701) (e7da0f0)

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🤖 Release is at https://github.com/googleapis/python-bigquery-dataframes/releases/tag/v1.8.0 🌻

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