build: Update lower bound of pyhf to v0.7.0rc2

[matthewfeickert]

v0.7.0rc2 fixes a regression in staterror introduced after v0.6.3 and so is present in v0.7.0rc1.

[codecov]

Codecov Report

Base: 100.00% // Head: 100.00% // No change to project coverage 👍

Coverage data is based on head (fd3c197) compared to base (84c7367).
Patch has no changes to coverable lines.

❗ Current head fd3c197 differs from pull request most recent head d2fa5f8. Consider uploading reports for the commit d2fa5f8 to get more accurate results

Additional details and impacted files

@@            Coverage Diff            @@
##            master      #361   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           23        23           
  Lines         2010      2009    -1     
  Branches       327       326    -1     
=========================================
- Hits          2010      2009    -1     

Impacted Files	Coverage Δ
src/cabinetry/workspace.py	100.00% <0.00%> (ø)

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[alexander-held]

Thanks for propagating this update (and the RC of course)!

* update lower bound of pyhf to v0.7.0rc2 to fix staterror regression