Fix rastervision.core dependencies

[AdeelH]

Overview

This PR makes some fixes to rastervision.core's dependencies.

Checklist

• Added needs-backport label if PR is bug fix that applies to previous minor release
• Ran scripts/format_code and committed any changes
• Documentation updated if needed
• PR has a name that won't get you publicly shamed for vagueness

Notes

N/A

Testing Instructions

• Check if CI passes.

[codecov]

Codecov Report

Merging #1920 (f6f1342) into master (b334d68) will increase coverage by 0.01%.
Report is 1 commits behind head on master.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1920      +/-   ##
==========================================
+ Coverage   82.48%   82.50%   +0.01%     
==========================================
  Files         190      190              
  Lines        9313     9316       +3     
==========================================
+ Hits         7682     7686       +4     
+ Misses       1631     1630       -1     

Files Changed	Coverage Δ
...ervision_core/rastervision/core/data/utils/misc.py	85.24% <100.00%> (+0.37%)	⬆️
...rvision/pytorch_backend/pytorch_learner_backend.py	62.12% <100.00%> (ø)

... and 1 file with indirect coverage changes