Merge pull request #126 from arduino/per1234/correct-env-docs

Update configuration environment variable names in docs

Author: per1234

Diff for: docs/index.md

@@ -58,10 +58,10 @@ The `--report-file` flag causes **arduino-lint** to write the JSON output to the
 
 Additional configuration options intended for internal use or development can be set via environment variables:
 
-- `ARDUINO_CHECK_OFFICIAL` - Set to `"true"` to run the checks that only apply to official Arduino projects.
-- `ARDUINO_CHECK_LOG_LEVEL` - Messages with this level and above will be logged.
+- `ARDUINO_LINT_OFFICIAL` - Set to `"true"` to run the checks that only apply to official Arduino projects.
+- `ARDUINO_LINT_LOG_LEVEL` - Messages with this level and above will be logged.
   - Supported values: `trace`, `debug`, `info`, `warn`, `error`, `fatal`, `panic`
-- `ARDUINO_CHECK_LOG_FORMAT` - The output format for the logs.
+- `ARDUINO_LINT_LOG_FORMAT` - The output format for the logs.
   - Supported values: `text`, `json`
 
 ## Continuous integration