Update matplotlib cache and tests

[YigitElma]

• Adds more recent versions of matplotlib to test_mpl
• In case there is no cached dependency, Set up virtual environment if not restored from cache step was installing latest matplotlib version. This PR fixes that
• Older versions were throwing error on int(matplotlib._version.version.split(".")[1]), this fixes the syntax

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.52%. Comparing base (d62cddd) to head (3ed9701).
Report is 3 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1312   +/-   ##
=======================================
  Coverage   95.52%   95.52%           
=======================================
  Files          96       96           
  Lines       24005    24005           
=======================================
  Hits        22930    22930           
  Misses       1075     1075           

Files with missing lines	Coverage Δ
desc/plotting.py	96.22% <100.00%> (ø)

... and 2 files with indirect coverage changes

[github-actions]

|             benchmark_name             |         dt(%)          |         dt(s)          |        t_new(s)        |        t_old(s)        | 
| -------------------------------------- | ---------------------- | ---------------------- | ---------------------- | ---------------------- |
 test_build_transform_fft_midres         |     -0.65 +/- 4.02     | -3.96e-03 +/- 2.43e-02 |  6.01e-01 +/- 1.7e-02  |  6.05e-01 +/- 1.7e-02  |
 test_build_transform_fft_highres        |     -1.47 +/- 4.13     | -1.50e-02 +/- 4.21e-02 |  1.01e+00 +/- 3.8e-02  |  1.02e+00 +/- 1.8e-02  |
 test_equilibrium_init_lowres            |     +1.29 +/- 4.81     | +4.95e-02 +/- 1.84e-01 |  3.88e+00 +/- 1.6e-01  |  3.83e+00 +/- 9.2e-02  |
 test_objective_compile_atf              |     +1.32 +/- 4.79     | +1.02e-01 +/- 3.70e-01 |  7.83e+00 +/- 3.0e-01  |  7.73e+00 +/- 2.2e-01  |
 test_objective_compute_atf              |     +2.07 +/- 2.42     | +2.15e-04 +/- 2.52e-04 |  1.06e-02 +/- 1.8e-04  |  1.04e-02 +/- 1.8e-04  |
 test_objective_jac_atf                  |     -1.17 +/- 3.05     | -2.24e-02 +/- 5.82e-02 |  1.89e+00 +/- 4.4e-02  |  1.91e+00 +/- 3.9e-02  |
 test_perturb_1                          |     +0.61 +/- 3.99     | +7.67e-02 +/- 5.01e-01 |  1.26e+01 +/- 4.5e-01  |  1.26e+01 +/- 2.3e-01  |
 test_proximal_jac_atf                   |     -0.35 +/- 0.77     | -2.81e-02 +/- 6.22e-02 |  8.05e+00 +/- 4.7e-02  |  8.07e+00 +/- 4.1e-02  |
 test_proximal_freeb_compute             |     +0.73 +/- 1.38     | +1.33e-03 +/- 2.51e-03 |  1.83e-01 +/- 2.4e-03  |  1.82e-01 +/- 7.3e-04  |
 test_build_transform_fft_lowres         |     +0.68 +/- 6.03     | +3.86e-03 +/- 3.40e-02 |  5.68e-01 +/- 2.8e-02  |  5.64e-01 +/- 2.0e-02  |
 test_equilibrium_init_medres            |     +1.66 +/- 4.03     | +7.31e-02 +/- 1.78e-01 |  4.49e+00 +/- 6.6e-02  |  4.41e+00 +/- 1.7e-01  |
 test_equilibrium_init_highres           |     +1.79 +/- 2.23     | +1.01e-01 +/- 1.26e-01 |  5.74e+00 +/- 8.0e-02  |  5.64e+00 +/- 9.7e-02  |
 test_objective_compile_dshape_current   |     +1.30 +/- 1.29     | +5.10e-02 +/- 5.06e-02 |  3.97e+00 +/- 4.7e-02  |  3.92e+00 +/- 1.9e-02  |
 test_objective_compute_dshape_current   |     +4.03 +/- 6.61     | +1.49e-04 +/- 2.44e-04 |  3.84e-03 +/- 2.1e-04  |  3.69e-03 +/- 1.3e-04  |
 test_objective_jac_dshape_current       |     -1.06 +/- 10.36    | -4.45e-04 +/- 4.34e-03 |  4.15e-02 +/- 3.0e-03  |  4.19e-02 +/- 3.1e-03  |
 test_perturb_2                          |     +2.55 +/- 2.07     | +4.62e-01 +/- 3.75e-01 |  1.86e+01 +/- 2.9e-01  |  1.81e+01 +/- 2.4e-01  |
 test_proximal_freeb_jac                 |     +2.10 +/- 1.43     | +1.56e-01 +/- 1.06e-01 |  7.56e+00 +/- 1.0e-01  |  7.41e+00 +/- 3.2e-02  |
 test_solve_fixed_iter                   |     +0.03 +/- 60.51    | +1.37e-03 +/- 3.03e+00 |  5.01e+00 +/- 2.1e+00  |  5.01e+00 +/- 2.2e+00  |