Read-only HDF5 file access for Hdf5History.__len__

[dweindl]

That function doesn't need write access to the history file and unnecessarily prevents parallel access.
Changing to read-only.

[PaulJonasJost]

Yes sorry that is on me. Thanks for the fix 👍

[codecov-commenter]

Codecov Report

Merging #679 (eb86010) into develop (a4a2070) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff            @@
##           develop     #679   +/-   ##
========================================
  Coverage    90.32%   90.32%           
========================================
  Files           96       96           
  Lines         6366     6366           
========================================
  Hits          5750     5750           
  Misses         616      616           

Impacted Files	Coverage Δ
pypesto/objective/history.py	95.36% <100.00%> (ø)

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[yannikschaelte]

@PaulJonasJost had fixed it swhere else already, but twice is better

[PaulJonasJost]

@PaulJonasJost had fixed it swhere else already, but twice is better

Oh yes you are right :D but the PR is still open.