fix: pyhf 0.7 compatibility

[alexander-held]

This updates cabinetry to be compatible with the upcoming pyhf version 0.7.0, and with the existing 0.7.0rc1.

scikit-hep/pyhf#1625 changed the order of model parameters, so the tests are updated to work with the new parameter order.

scikit-hep/pyhf#1639 changed paramset.suggested_fixed, the previous functionality is now achieved via suggested_fixed_as_bool.

CI temporarily failed due to changes in scikit-hep/pyhf#1639 that affect the model.config.suggested_fixed API return types, see scikit-hep/pyhf#1701 for details. Fixed via scikit-hep/pyhf#1706.

Integration test tolerances are slightly relaxed due to small differences seen between different local setups (see also #318).

resolves #340 (nothing in particular needed in this PR to achieve that, but pyhf 0.7 will resolve #340 so that problem will disappear within cabinetry as well after this PR)

resolves #344

* updated parameter order in tests to match order in pyhf 0.7.0
* adopted new paramset.suggested_fixed_as_bool API

[codecov]

Codecov Report

Merging #301 (e2b42a6) into master (598c06c) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##            master      #301   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           23        23           
  Lines         1876      1876           
  Branches       298       298           
=========================================
  Hits          1876      1876           

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

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[alexander-held]

The last piece of pyhf 0.7 API compatibility, model.config.par_names, was added in #367.