Prepare next release 1.12.0.

List of issues / PR to include:

• [BUILD] Need fine-grained HAVE_CPP_STDLIB #2304
• [API] Add InstrumentationScope attributes in MeterProvider::GetMeter() #2224
• [REMOVAL] Drop C++11 support #2342
• [BUILD] error: read-only reference ‘value’ used as ‘asm’ output #2354
• [BUILD] Build break with external CMake nlohman_json package #2353
• [BUILD] Upgrade libcurl to version 8.4.0 #2358

Tentative:

• [BUILD] Support to use different cmake package CONFIG of dependencies. #2263

Please comment on any PR that should be included as well.

Planning to release on week 40 (first week of October)