Fix C++20 incompatibilities in IO extensions

[fmorgner]

Description

Replace the simple-template-ids used in the IO extension tags as constructor names for specializations of image_read_info and image_read_settings with the associated plain class names.

References

resolves #616

Tasklist

• Ensure all CI builds pass
• Review and approve

[sdebionne]

LGTM and thanks for the fix! I remember asking myself what were this image_read_info< xxx_tag >() ctor about but they were armless at the time.

[codecov]

Codecov Report

Merging #617 (effd078) into develop (7dd6120) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff            @@
##           develop     #617   +/-   ##
========================================
  Coverage    78.72%   78.72%           
========================================
  Files          118      118           
  Lines         5034     5034           
========================================
  Hits          3963     3963           
  Misses        1071     1071           

[fmorgner]

I believe the build issues in CI / windows (msvc-14.2, 14,17,latest, 32,64, windows-2019) are the same as on the develop branch, while CI / posix (clang, clang++-9, 11,14,17,2a, ubuntu-20.04) seems to have an issue with a missing clang-9 installation.

[sdebionne]

From what I read on slack, the GHA guys have fun changing the docker images without notice. I am not a CI guru, @mloskot can this be easily fixed? Apparently develop currently fails with the same error with clang-8/clang-9.

[sdebionne]

@mloskot I'd like to merge this one, any objection?

[mloskot]

LGTM. Thanks!

[mloskot]

@sdebionne Please, do. Thank you for nudging me about it.

Sorry, I have no having any solution for the CI issues right now. I should be able to look at that next month.

[sdebionne]

@mloskot No worries and unfortunately I don't have time to look at the CI neither... but this should be safe to merge.