Update to OPTIMADE Python tools v0.7.0

[CasperWA]

Slightly new Python tools API and new grammar term.

[codecov]

Codecov Report

Merging #62 into develop will increase coverage by 0.03%.
The diff coverage is 85.71%.

@@             Coverage Diff             @@
##           develop      #62      +/-   ##
===========================================
+ Coverage    69.30%   69.34%   +0.03%     
===========================================
  Files           15       15              
  Lines          808      809       +1     
===========================================
+ Hits           560      561       +1     
  Misses         248      248              

Flag	Coverage Δ
#unittests	69.34% <85.71%> (+0.03%)	⬆️

Impacted Files	Coverage Δ
aiida_optimade/transformers/aiida.py	84.90% <83.33%> (+0.14%)	⬆️
aiida_optimade/mappers/entries.py	100.00% <100.00%> (ø)

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