Add bqplot-gl to install_requires

[dhomeier]

Description

Follow-up to #302; this will be needed once bqplot 0.13 is out, which is currently in alpha.
As discussed in #377 with the placeholder package bqplot-gl 0.0.0 available, this can be added to the requirements.
If someone has a bqplot>=0.13.0a0 installed, they will need to manually pick the alpha version or directly install
'bqplot-gl==0.1.0a0 first.

[codecov]

Codecov Report

Patch and project coverage have no change.

Comparison is base (0be614f) 86.91% compared to head (b86c76a) 86.91%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #385   +/-   ##
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  Coverage   86.91%   86.91%           
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  Files          89       89           
  Lines        4990     4990           
=======================================
  Hits         4337     4337           
  Misses        653      653           

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[pllim]

@dhomeier , can you at least do a pre-release with this patch, so running Jdaviz with pre-releases do not crash?

See https://github.com/spacetelescope/jdaviz/actions/runs/6010161651/job/16301044292

bqplot==0.13.0a0
...
glue_jupyter/bqplot/compatibility.py:8: in <module>
    import bqplot_gl
E   ModuleNotFoundError: No module named 'bqplot_gl'