Brotli streaming decompression: use output_buffer_limit

This became possible with brotli 1.2.0

It is my understanding pre-this change there was basically no
enforced limit on the amount of bytes "coming out" of
decompressor.process(); in other words: chunk size did not
apply to the most relevant (potentially blowing up) part of
the equation.

We had a MaxDataReader in place, but that would come "too late"
since all the mem-consuming stuff would happen right in brotli_generator
before any limiting would be possible.

See https://github.com/google/brotli/issues/1381

requirements.txt

@@ -7,7 +7,7 @@ semver==3.0.*
 django-admin-autocomplete-filter==0.7.*
 pygments==2.19.*
 inotify_simple==2.0.*
-Brotli==1.1.*
+Brotli==1.2.*
 python-dateutil==2.9.*
 whitenoise==6.11.*
 requests==2.32.*