Introduce loading config from env var GITLEAKS_CONFIG #745
Description
Describe the solution you'd like
Users should be able to load a global config if GITLEAKS_CONFIG env var is set
-c, --config string config file path
order of precedence:
1. --config/-c
2. env var `GITLEAKS_CONFIG`
3. (--source/-s)/.gitleaks.toml
Additional context
If the user does not provide a config path from one of the three options then the default config will be used.
cc @zricethezav