add upper bound to bokeh version

[OriolAbril]

Description

Follow up from #1953, set an upper bound to bokeh version
for now until making the change, updating the code and requiring version 3.

Checklist

• Does the PR follow official PR format?
• Is the code style correct (follows pylint and black guidelines)?
• Is the fix listed in the Maintenance and fixes section of the changelog?

[codecov]

Codecov Report

Merging #1954 (ca2de2c) into main (26c14da) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main    #1954   +/-   ##
=======================================
  Coverage   91.51%   91.51%           
=======================================
  Files         113      113           
  Lines       12231    12231           
=======================================
  Hits        11193    11193           
  Misses       1038     1038           

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