feat: set fsspec (s3fs) as default handler for s3 paths (#1032)

* feat: add fsspec as required dependency (#1021)

* fsspec requirements

* simplify fsspec import

* use loop property

* correctly create schemes list

* feat: set fsspec as default source (#1023)

* feat: add fsspec as required dependency (#1021)

* fsspec requirements

* simplify fsspec import

* use loop property

* correctly create schemes list

* remove deprecated handlers from docs

* simplify source selection

* return object source

* pickle executor

* rename test

* test more handlers

* option to check writeable file-like object

* rename test

* explicitly set handler

* fix s3 source

* rename test

* Revert "fix s3 source"

This reverts commit e76fdbb.

* sesparate PR for s3 fix (#1024)

* strip file://

* rename test

* rename tests

* add aiohttp skip

* attempt to parse windows paths

* test ci

* Revert "test ci"

This reverts commit 4c1c8a5.

* rename test

* remove fsspec from test

* remove *_handler options

* update defaults

* do not override default s3

* do not use fsspec for multiprocessing

* rename test

* fix not selecting object source

* missing import

* normalize doc

* remove helper

* never return None as source

* remove unnecessary xrootd source default override since fsspec is default now

* rename test

* add empty class to pass old pickle test

* set version to 5.2.0rc1 (release candidate)

* set s3fs as default for s3

* test different handlers

* correct serialization of fsspec source

src/uproot/_util.py

@@ -435,8 +435,8 @@ def file_path_to_source_class(file_path, options):
         return source_cls, file_path
 
     elif scheme == "s3":
-        # https://github.com/scikit-hep/uproot5/pull/1012
-        source_cls = uproot.source.s3.S3Source
+        # uproot.source.s3.S3Source
+        source_cls = uproot.source.fsspec.FSSpecSource
         return source_cls, file_path
 
     elif scheme in ("http", "https"):

src/uproot/version.py

@@ -12,7 +12,7 @@
 
 import re
 
-__version__ = "5.1.2"
+__version__ = "5.2.0rc1"
 version = __version__
 version_info = tuple(re.split(r"[-\.]", __version__))