requirements: Add service_identity to scrapy.txt.

[hackerkid]

No description provided.

[codecov-io]

Codecov Report

Merging #5465 into master will decrease coverage by 0.03%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #5465      +/-   ##
==========================================
- Coverage   86.55%   86.51%   -0.04%     
==========================================
  Files         430      430              
  Lines       53043    53043              
  Branches     2066     2066              
==========================================
- Hits        45912    45891      -21     
- Misses       7131     7152      +21

Impacted Files	Coverage Δ
zerver/tornado/ioloop_logging.py	46.66% <0%> (-46.67%)	⬇️

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[showell]

merged, thanks @hackerkid!

[timabbott]

@hackerkid what does this do? In the future, please provide more detail in the rest of a commit message explaining the purpose of changes.

[showell]

Just to provide some context, this was sort of an emergency fix, but, yeah, we probably should have put more detail in the commit message, and I should have asked for more detail before merging.