chore(dep): Unpin slackclient dependency

[ecederstrand]

SUMMARY

This is the last of three PRs, attempting to unpin Superset dependencies. See also #21581 and #21091

slackclient was originally pinned in #10345 due to slackapi/python-slack-sdk#728 which was fixed in a series of PRs concluding with slackapi/python-slack-sdk#901 which was released in slack_sdk version 3.1.1.

slack_sdk no longer depends on aiohttp, which removes a handful of dependencies.

While here, make tabulate and holidays dependency versions open-ended. This leaves only numpy pinned in install_requires in setup.py.

[villebro]

Awesome work, that stale Slack library had started to annoy me, too 🙂 Left a few comments, LMKWYT.

[villebro]

Tagging @dpgaspar and @bkyryliuk for additional reviews to validate for potential regressions caused by the Slack client major bump.

[codecov]

Codecov Report

Merging #21586 (a20ef41) into master (954fc89) will decrease coverage by 1.43%.
The diff coverage is 40.00%.

❗ Current head a20ef41 differs from pull request most recent head 3546c50. Consider uploading reports for the commit 3546c50 to get more accurate results

@@            Coverage Diff             @@
##           master   #21586      +/-   ##
==========================================
- Coverage   66.65%   65.22%   -1.44%     
==========================================
  Files        1794     1794              
  Lines       68721    68713       -8     
  Branches     7318     7312       -6     
==========================================
- Hits        45804    44816     -988     
- Misses      21055    22029     +974     
- Partials     1862     1868       +6     

Flag	Coverage Δ
hive	?
mysql	78.21% <40.00%> (?)
postgres	78.27% <40.00%> (ø)
presto	?
python	78.40% <40.00%> (-2.91%)	⬇️
sqlite	76.77% <40.00%> (?)
unit	?

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
superset/tasks/slack_util.py	0.00% <0.00%> (ø)
superset/reports/notifications/slack.py	88.00% <100.00%> (ø)
superset/tables/schemas.py	0.00% <0.00%> (-100.00%)	⬇️
superset/columns/schemas.py	0.00% <0.00%> (-100.00%)	⬇️
superset/db_engines/hive.py	0.00% <0.00%> (-85.19%)	⬇️
...set/advanced_data_type/plugins/internet_address.py	16.32% <0.00%> (-79.60%)	⬇️
superset/utils/pandas_postprocessing/boxplot.py	20.51% <0.00%> (-79.49%)	⬇️
superset/charts/post_processing.py	11.76% <0.00%> (-77.95%)	⬇️
...perset/advanced_data_type/plugins/internet_port.py	18.75% <0.00%> (-77.09%)	⬇️
superset/utils/pandas_postprocessing/rolling.py	21.87% <0.00%> (-68.75%)	⬇️
... and 63 more

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[villebro]

LGTM with one last optional comment

[ecederstrand]

Ping @dpgaspar @bkyryliuk Does anything need fixing in this PR?

[dpgaspar]

Verified that charts are sent to Slack with the new sdk