Fix schema type for BaseCSVFilter/ModelChoiceFilter

[wonderbeyond]

I can not type csv numbers in swagger-ui, so I made this change.

[codecov-io]

Codecov Report

Merging #1202 into master will decrease coverage by 0.07%.
The diff coverage is 66.66%.

@@            Coverage Diff             @@
##           master    #1202      +/-   ##
==========================================
- Coverage   99.44%   99.36%   -0.08%     
==========================================
  Files          15       15              
  Lines        1255     1257       +2     
==========================================
+ Hits         1248     1249       +1     
- Misses          7        8       +1     

Impacted Files	Coverage Δ
django_filters/rest_framework/backends.py	98.92% <66.66%> (-1.08%)	⬇️

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[codecov-commenter]

Codecov Report

Merging #1202 into master will decrease coverage by 0.07%.
The diff coverage is 66.66%.

@@            Coverage Diff             @@
##           master    #1202      +/-   ##
==========================================
- Coverage   99.44%   99.36%   -0.08%     
==========================================
  Files          15       15              
  Lines        1253     1255       +2     
==========================================
+ Hits         1246     1247       +1     
- Misses          7        8       +1     

Impacted Files	Coverage Δ
django_filters/rest_framework/backends.py	98.92% <66.66%> (-1.08%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 79b4ea7...d57fdf0. Read the comment docs.

[wonderbeyond]

Add schema fix for ModelChoiceFilter just now.

[carltongibson]

Hi @wonderbeyond — Thanks for this.

We need to fix #1243 for the CI, but beyond that I guess we can take this. (The CoreAPI schemas will stop working eventually but you can pin to the last versions that support whilst you're still using them.)

[wonderbeyond]

Hi @carltongibson can my PR been merged now?

[carltongibson]

As per #1432 the in-built schema support is going to be deprecated in the next version.

Rather, I recommend you migrate to use drf-spectacular, which is much more fully featured, and under active development.

https://drf-spectacular.readthedocs.io/en/latest/readme.html

If for some reason you're not able to use drf-spectacular you can copy the django_filters.rest_framework.backends.DjangoFilterBackend into your own project to customise as needed. (But use drf-spectacular.)

Thanks.