Remove requirement mypy < 0.920

[dafeda]

Issue
Resolves #my_issue

Approach
Short description of the approach

Pre review checklist

• [ x] Added appropriate labels

Adding labels helps the maintainers when writing release notes, see sections and the
corresponding labels here: https://github.com/equinor/ert/blob/main/.github/release.yml

[sondreso]

LGTM

[codecov-commenter]

Codecov Report

Merging #3090 (f19afee) into main (daf7551) will increase coverage by 0.00%.
The diff coverage is 66.66%.

❗ Current head f19afee differs from pull request most recent head 65801eb. Consider uploading reports for the commit 65801eb to get more accurate results

@@           Coverage Diff           @@
##             main    #3090   +/-   ##
=======================================
  Coverage   65.41%   65.41%           
=======================================
  Files         651      651           
  Lines       50791    50794    +3     
  Branches     4477     4477           
=======================================
+ Hits        33223    33227    +4     
  Misses      16059    16059           
+ Partials     1509     1508    -1     

Impacted Files	Coverage Δ
ert3/config/_config_plugin_registry.py	85.88% <66.66%> (-0.71%)	⬇️
libres/lib/res_util/block_fs.cpp	53.97% <0.00%> (+0.14%)	⬆️
ert/data/record/_transformation.py	88.72% <0.00%> (+0.49%)	⬆️

📣 Codecov can now indicate which changes are the most critical in Pull Requests. Learn more

[dafeda]

test this please