Isort

- isort now throws an exception if an invalid settings path is given (issue 1174).
- Implemented support for automatic redundant alias removal (issue 1281).
- Implemented experimental support for floating all imports to the top of a file (issue 1228)
- Fixed 1178: support for semicolons in decorators.
- Fixed 1315: Extra newline before comment with -n + --fss.
- Fixed 1192: `-k` or `--keep-direct-and-as-imports` option has been deprecated as it is now always on.

Formatting changes implied:
- Fixed 1280: rewrite of as imports changes the behavior of the imports.

- Fixed 1301: Import headings in nested sections leads to check errors

- Fixed 1277 & 1278: New line detection issues on Windows.
- Fixed 1294: Fix bundled git hook.

- Fixed 1306: unexpected --diff behavior.
- Fixed 1279: Fixed NOQA comment regression.

- Fixed 1302: comments and --trailing-comma can generate invalid code.
- Fixed 1293: extra new line in indented imports, when immediately followed by a comment.
- Fixed 1304: isort 5 no longer recognises `sre_parse` as a stdlib module.
- Fixed 1300: add_imports moves comments following import section.
- Fixed 1276: Fix a bug that creates only one line after triple quotes.

- Fixed 1285: packaging issue with bundling tests via poetry.
- Fixed 1284: Regression when sorting `.pyi` files from CLI using black profile.
- Fixed 1275 & 1283: Blank line after docstring removed.
- Fixed 1298: CLI Help out of date with isort 5.
- Fixed 1290: Unecessary blank lines above nested imports when import comments turned on.
- Fixed 1297: Usage of `--add-imports` alongside `--check` is broken.
- Fixed 1289: Stream usage no longer auto picking up config file from current working directory.
- Fixed 1296: Force_single_line setting removes immediately following comment line.
- Fixed 1295: `ensure_newline_before_comments` doesnt work with `force_sort_within_sections`.
- Setting not_skip will no longer immediately fail but instead give user a warning and direct
to upgrade docs.