docs: add publish step

[nytai]

SUMMARY

Adds a step to publish docs after merges to master. Uses https://github.com/cpina/github-action-push-to-another-repository github action to push to the https://github.com/apache/superset-site repo

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

N/A

TEST PLAN

• Tested using target branch https://github.com/apache/superset-site/tree/test-branch

ADDITIONAL INFORMATION

• Has associated issue: Fixes Setup Auto-Deploy Superset Documentation #13599
• Changes UI
• Includes DB Migration (follow approval process in SIP-59)
  • Migration is atomic, supports rollback & is backwards-compatible
  • Confirm DB migration upgrade and downgrade tested
  • Runtime estimates and downtime expectations provided
• Introduces new feature or API
• Removes existing feature or API

[codecov]

Codecov Report

Merging #14304 (b03515f) into master (86233d1) will increase coverage by 0.08%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #14304      +/-   ##
==========================================
+ Coverage   76.93%   77.02%   +0.08%     
==========================================
  Files         954      954              
  Lines       48074    48074              
  Branches     5974     5974              
==========================================
+ Hits        36986    37027      +41     
+ Misses      10891    10850      -41     
  Partials      197      197              

Flag	Coverage Δ
hive	80.45% <ø> (ø)
javascript	72.10% <ø> (ø)
mysql	80.73% <ø> (ø)
postgres	80.77% <ø> (ø)
presto	80.47% <ø> (?)
python	81.31% <ø> (+0.15%)	⬆️
sqlite	80.37% <ø> (ø)

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

Impacted Files	Coverage Δ
superset/models/core.py	89.13% <0.00%> (+0.27%)	⬆️
superset/connectors/sqla/models.py	90.07% <0.00%> (+1.45%)	⬆️
superset/db_engine_specs/presto.py	90.31% <0.00%> (+5.89%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 86233d1...b03515f. Read the comment docs.