Disable GET method for unarchiving

[reupen]

The front end is using POST now so GET can be removed.

[codecov-io]

Codecov Report

Merging #272 into develop will not change coverage.
The diff coverage is 100%.

@@           Coverage Diff            @@
##           develop     #272   +/-   ##
========================================
  Coverage    93.38%   93.38%           
========================================
  Files           58       58           
  Lines         2115     2115           
  Branches       194      194           
========================================
  Hits          1975     1975           
- Misses         117      118    +1     
+ Partials        23       22    -1

Impacted Files	Coverage Δ
datahub/company/urls.py	100% <ø> (ø)	⬆️
datahub/core/mixins.py	100% <100%> (ø)	⬆️
datahub/company/admin.py	89.47% <0%> (ø)	⬆️

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[canni]

If we're disabling previously available calls I feel like there should be a test testing a 405 response for GET method

[canni]

+1