Release 0.7.0

Highlights:

• Initial support for Zephyr targets

Added:

• rpc: add unit tests
• zephyr: add Zephyr port
• zephyr: add DFU support
• examples: add golioth_basics example for Zephyr
• golioth_coap_client: introduce GOLIOTH_OVERRIDE_LIBCOAP_LOG_HANDLER
• remote_shell: add CONFIG_GOLIOTH_REMOTE_SHELL_THREAD_STACK_SIZE
• ota: add CONFIG_GOLIOTH_OTA_THREAD_STACK_SIZE

Changed:

• treewide: change 'task' nomenclature to thread
• treewide: replace '#define TAG ...' with LOG_TAG_DEFINE(...)
• esp_idf: convert GOLIOTH_REMOTE_SHELL_ENABLE to bool
• port: modus_toolbox: define HAVE_PTHREAD_{H,MUTEX_LOCK}
• port: esp_idf: define HAVE_PTHREAD_{H,MUTEX_LOCK}
• port: remove COAP_RESOURCES_NOHASH definition
• README: clarify the support for OTA on Linux
• libcoap: bump to tip of develop branch

Fixed:

• settings: allow float type settings to be whole numbers
• settings: update device_settings_register_bool docstring
• ota: fix typo in error message when creating thread
• scripts: only suggest running clang-format on noncompliant files
• rpc: fixed typos in doc strings