Log Message:
subfinder: Update to 2.6.1

Changes:
v2.6.1
## What's Changed
### Bug Fixes
* Fixed panic issue with digitorus source
* Fixed issue parsing result from securitytrails

v2.6.0
## What's Changed
* Added `netlas.io` as new source
* Added support to use provider config file when using as library
* Added support to read API keys as env variable in the provider config file

```yaml
netlas:
  - $NETLAS_API_KEY
```

v2.5.9
## What's Changed
* Added support to extract additional subdomains from digitorus source
* Added tests for sources require an api key
* Fixed issue with the close method for session
* Fixed issue with case insensitive subdomain result
* Fixed issue with securitytrails api