[Chore] tag v3.6.0 (20230830) (#255)
Commits from v3.5.1 to v3.6.0
* Bug fix
1. [Fix] boot_ctrl.cboot: post_update error handling #240
2. [Fix] otaclient_stub: fix always export self ECU id in available_ecu_ids #250
* Features
1. [Feature] extend ota-file-cache-control header #244
2. [Feature & Refinement] otaproxy: OTA file sha256 aware, support new header #245
3. [Feature & Refinement] otaproxy, otaclient: introduce external cache dev support #246
* Chore
1. doc: update document especially available_ecu_ids #248
2. [Chore] tools: add new OTA status monitor #251
3. [Chore] tools: add offline OTA image builder #252
* Deps
1. Bump grpcio from 1.40.0 to 1.53.0 in /tools/emulator #241
2. [Deps] bumps grpcio to 1.53.1 #243
3. Bump aiohttp from 3.8.1 to 3.8.5 in /otaclient #247
