DOC: Remove travis doc build

[datapythonista]

In #26648 we started building the documentation in azure pipelines. Seems to work fine, removing the travis build here.

[jreback]

did you fix the doc links in contributing guide to show the new site?

[datapythonista]

Just opened #26857 for that.

[codecov]

Codecov Report

Merging #26856 into master will decrease coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #26856      +/-   ##
==========================================
- Coverage   91.88%   91.87%   -0.01%     
==========================================
  Files         179      179              
  Lines       50696    50696              
==========================================
- Hits        46581    46577       -4     
- Misses       4115     4119       +4

Flag	Coverage Δ
#multiple	90.46% <ø> (ø)	⬆️
#single	41.09% <ø> (-0.09%)	⬇️

Impacted Files	Coverage Δ
pandas/io/gbq.py	88.88% <0%> (-11.12%)	⬇️
pandas/core/frame.py	96.88% <0%> (-0.12%)	⬇️

---

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[codecov]

Codecov Report

Merging #26856 into master will decrease coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #26856      +/-   ##
==========================================
- Coverage   91.87%   91.86%   -0.01%     
==========================================
  Files         180      180              
  Lines       50716    50716              
==========================================
- Hits        46594    46590       -4     
- Misses       4122     4126       +4

Flag	Coverage Δ
#multiple	90.45% <ø> (ø)	⬆️
#single	41.12% <ø> (-0.09%)	⬇️

Impacted Files	Coverage Δ
pandas/io/gbq.py	88.88% <0%> (-11.12%)	⬇️
pandas/core/frame.py	96.88% <0%> (-0.12%)	⬇️

---

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 49f33f0...c2d4fec. Read the comment docs.

[topper-123]

I got an https security warning on https://dev.pandas.io/. Anyone can confirm?

[datapythonista]

We've got #26841 for the TLS warning, didn't take a look yet.

[jreback]

did this need a rebase? the reason i ask is IIRC the travis file was updated, but not sure this matters here.

[datapythonista]

I rebased it today, this is up to date with master, except for any commit in the last couple of hours.

[jreback]

thanks @datapythonista