Add 'change-tariff' public API endpoint
CHANGELOG:
### Added
- [#531](https://gitlab.com/coopdevs/odoo-somconnexio/-/merge_requests/531) Add new public API endpoint to change tariffs from existing mobile contracts
Includes 'ChangeContractTariff' service, which is called both by change tariff wizard and change tariff API endpoint
# Setup
set -a
export BaseURL="http://url"
set +a
# Change tariff
curl \
-X POST \
-H 'Content-Type: application/json' \
-H 'Authorization: Basic xxxxxxxxx' \
--data '{
"phone_number": "xxxxxxx",
"product_code": "SE_SC_REC_MOBILE_T_150_2048"
}' \
"$BaseURL/public-api/change-tariff"
Edited by Pelayo García