mod_http_oauth2: Implement refresh token rotation Makes refresh tokens one-time-use, handing out a new refresh token with each access token. Thus if a refresh token is stolen and used by an attacker, the next time the legitimate client tries to use the previous refresh token, it will not work and the attack will be noticed. If the attacker does not use the refresh token, it becomes invalid after the legitimate client uses it. This behavior is recommended by draft-ietf-oauth-security-topics

This module provides two [metrics][doc:statistics]:

`lua_heap_bytes`
:   Bytes of memory as reported by `collectgarbage("count")`{.lua}

`lua_info`
:   Provides the current Lua version as a label

``` openmetrics
# HELP lua_info Lua runtime version
# UNIT lua_info
# TYPE lua_info gauge
lua_info{version="Lua 5.4"} 1
# HELP lua_heap_bytes Memory used by objects under control of the Lua
garbage collector
# UNIT lua_heap_bytes bytes
# TYPE lua_heap_bytes gauge
lua_heap_bytes 8613218
```