docs(news): tweak news (#539)

NEWS.md

@@ -6,8 +6,8 @@
   - changes in `$write_csv()` and `sink_csv()`: `has_header` is renamed
     `include_header` and there's a new argument `include_bom`.
   - `pl$cov()` gains a `ddof` argument.
-  - `$cumsum()`, `$cumprod()`, `$cummin()`, `$cummax()`, `$cumcount()`  are
-    renamed `$cum_sum()`, `$cum_prod()`, `$cum_min()`, `$cum_max()`, 
+  - `$cumsum()`, `$cumprod()`, `$cummin()`, `$cummax()`, `$cumcount()` are
+    renamed `$cum_sum()`, `$cum_prod()`, `$cum_min()`, `$cum_max()`,
     `$cum_count()`.
   - `take()` and `take_every()` are renamed `$gather()` and `gather_every()`.
   - `$shift()` and `$shift_and_fill()` now accept Expr as input.
@@ -19,19 +19,19 @@
 ## Breaking changes and deprecations
 
 - The rowwise computation when several columns are passed to `pl$min()`, `pl$max()`,
-  and `pl$sum()` is deprecated and will be removed in 0.12.0. Passing several 
-  columns to these functions will now compute the min/max/sum in each column 
-  separately. Use `pl$min_horizontal()` `pl$max_horizontal()`, and 
+  and `pl$sum()` is deprecated and will be removed in 0.12.0. Passing several
+  columns to these functions will now compute the min/max/sum in each column
+  separately. Use `pl$min_horizontal()` `pl$max_horizontal()`, and
   `pl$sum_horizontal()` instead for rowwise computation (#508).
-- `$is_not()` is deprecated and will be removed in 0.12.0. Use `$not()` instead 
+- `$is_not()` is deprecated and will be removed in 0.12.0. Use `$not()` instead
   (#511, #531).
 - `$is_first()` is deprecated and will be removed in 0.12.0. Use `$is_first_distinct()`
   instead (#531).
-- In `pl$concat()`, the argument `to_supertypes` is removed. Use the suffix 
+- In `pl$concat()`, the argument `to_supertypes` is removed. Use the suffix
   `"_relaxed"` in the `how` argument to cast columns to their shared supertypes
   (#523).
-- All duration methods (`days()`, `hours()`, `minutes()`, `seconds()`, 
-  `milliseconds()`, `microseconds()`, `nanoseconds()`) are renamed, for example 
+- All duration methods (`days()`, `hours()`, `minutes()`, `seconds()`,
+  `milliseconds()`, `microseconds()`, `nanoseconds()`) are renamed, for example
   from `$dt$days()` to `$dt$total_days()`. The old usage is deprecated and will
   be removed in 0.12.0.
 - DataFrame methods `$as_data_frame()` is removed in favor of `$to_data_frame()` (#533).
@@ -41,22 +41,23 @@
 
 ## What's changed
 
+- Fix the installation issue on Ubuntu 20.04 (#528, thanks @brownag).
 - New methods `$write_json()` and `$write_ndjson()` for DataFrame (#502).
 - Removed argument `name` in `pl$date_range()`, which was deprecated for a while
   (#503).
-- New private method `.pr$DataFrame$drop_all_in_place(df)` to drop `DataFrame` 
+- New private method `.pr$DataFrame$drop_all_in_place(df)` to drop `DataFrame`
   in-place, to release memory without invoking gc(). However, if there are other
-  strong references to any of the underlying Series or arrow arrays, that memory 
-  will specifically not be released. This method is aimed for r-polars extensions, 
+  strong references to any of the underlying Series or arrow arrays, that memory
+  will specifically not be released. This method is aimed for r-polars extensions,
   and will be kept stable as much as possible (#504).
 - New functions `pl$min_horizontal()`, `pl$max_horizontal()`, `pl$sum_horizontal()`,
   `pl$all_horizontal()`, `pl$any_horizontal()` (#508).
-- New generic functions `as_polars_df()` and `as_polars_lf()` to create polars 
+- New generic functions `as_polars_df()` and `as_polars_lf()` to create polars
   DataFrames and LazyFrames (#519).
 - New method `$ungroup()` for `GroupBy` and `LazyGroupBy` (#522).
-- New method `$rolling()` to apply an Expr over a rolling window based on 
+- New method `$rolling()` to apply an Expr over a rolling window based on
   date/datetime/numeric indices (#470).
-- New methods `$name$to_lowercase()` and `$name$to_uppercase()` to transform 
+- New methods `$name$to_lowercase()` and `$name$to_uppercase()` to transform
   variable names (#529).
 - New method `$is_last_distinct()` (#531).
 - New methods of the Expressions class, `$floor_div()`, `$mod()`, `$eq_missing()`