better handling of pickle5 backport

[epassaro]

Description

• pyne macOS deprecation is still giving us problems (now with @KevinCawley and the numba integration pipeline). I don't think this patch is enough to fix our problems, but provides a better handling of the hack.

• Moved pickle5 from pip section of the environment file (solves Broken environment definition file #1564).

Motivation and context
See #1535.

How has this been tested?

• Testing pipeline.
• Other.

Examples

Type of change

• Bug fix.
• New feature.
• Breaking change.
• None of the above.

Checklist

• My change requires a change to the documentation.
  • I have updated the documentation accordingly.
  • (optional) I have built the documentation on my fork following the instructions.
• I have assigned and requested two reviewers for this pull request.

[codecov]

Codecov Report

Merging #1566 (a73eb95) into master (92b7e1d) will decrease coverage by 1.18%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1566      +/-   ##
==========================================
- Coverage   68.24%   67.05%   -1.19%     
==========================================
  Files          73       73              
  Lines        6373     6144     -229     
==========================================
- Hits         4349     4120     -229     
  Misses       2024     2024              

Impacted Files	Coverage Δ
...ntecarlo/montecarlo_numba/frame_transformations.py	35.00% <0.00%> (-13.00%)	⬇️
...s/tardis/montecarlo/montecarlo_numba/estimators.py	43.75% <0.00%> (-8.89%)	⬇️
...montecarlo/montecarlo_numba/calculate_distances.py	23.07% <0.00%> (-7.16%)	⬇️
.../tardis/montecarlo/montecarlo_numba/interaction.py	28.20% <0.00%> (-5.13%)	⬇️
.../montecarlo/montecarlo_numba/single_packet_loop.py	27.11% <0.00%> (-3.53%)	⬇️
...is/tardis/montecarlo/montecarlo_numba/opacities.py	80.00% <0.00%> (-3.34%)	⬇️
...dis/tardis/montecarlo/montecarlo_numba/r_packet.py	25.21% <0.00%> (-2.44%)	⬇️
...rdis/tardis/montecarlo/montecarlo_numba/vpacket.py	17.47% <0.00%> (-2.34%)	⬇️
tardis/tardis/plasma/properties/util/macro_atom.py	29.03% <0.00%> (-2.22%)	⬇️
...rdis/montecarlo/montecarlo_numba/tests/conftest.py	91.11% <0.00%> (-1.88%)	⬇️
... and 37 more

---

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 92b7e1d...a73eb95. Read the comment docs.