This changes the defaults:
- AUTOENV_ENV_FILENAME: .env_auth => .autoenv_auth
- AUTOENV_FILE_ENTER: .env => .autoenv.zsh
- AUTOENV_FILE_LEAVE: .env_leave => .autoenv_leave.zsh
`.env` is usually used only for key-value pairs for environment
settings, e.g. with foreman. We do not want to interfere with this.
Fixes https://github.com/Tarrasch/zsh-autoenv/issues/31.
- Support for leave event, via DOTENV_FILE_LEAVE and _dotenv_event (can
use DOTENV_FILE_LEAVE=$DOTENV_FILE_ENTER).
- Support for searching upwards for $DOTENV_FILE_ENTER (#3).
- Source .env only once per session, but re-source when leave events
are enabled (#1).
- Trigger the machinery when the script gets sourced, for the current
dir (#2).