docs-requirements: fix warning with remoulade > 5 (#4466)

This warns locally because `RateLimitEnqueue` has been moved to an
optional package:

sphinx.errors.SphinxWarning: autodoc: failed to import module 'remoulade' from module 'opentelemetry.instrumentation'; the following exception was raised:
cannot import name 'RateLimitEnqueue' from 'remoulade.rate_limits' (/home/rm/src/opentelemetry-python-contrib/.tox/docs/lib/python3.12/site-packages/remoulade/rate_limits/__init__.py)

Author: xrmx

docs-requirements.txt

@@ -44,7 +44,8 @@ PyMySQL~=1.1.1
 pymssql~=2.3.2
 pyramid>=1.7
 redis>=2.6
-remoulade>=0.50
+remoulade[limits]>=5.0.0 ; python_version >= "3.12"
+remoulade>=0.50.0 ; python_version < "3.12"
 sqlalchemy>=1.0
 starlette~=0.50
 tornado>=5.1.1