Update configuration docs

Author: MrAlias

docs/configuration.md

@@ -10,10 +10,13 @@ Alternatively, you can add support for additional or different configurations by
 
 | Environment variable        | Description                                                                | Default value |
 |-----------------------------|----------------------------------------------------------------------------|---------------|
-| `OTEL_GO_AUTO_TARGET_EXE`   | Sets the binary for the Go application to be instrumented. Required.       | Unset         |
+| `OTEL_GO_AUTO_TARGET_PID`   | Sets the PID for the Go application to be instrumented. As an alternative to using the environment variable, you can use the `-target-pid` CLI flag.[^1]. | Unset         |
+| `OTEL_GO_AUTO_TARGET_EXE`   | Sets the binary for the Go application to be instrumented. As an alternative to using the environment variable, you can use the `-target-exe` CLI flag.[^1]. | Unset         |
 | `OTEL_GO_AUTO_GLOBAL`       | Records telemetry from the OpenTelemetry default global implementation. As an alternative to using the environment variable, you can use the `-global-impl` CLI flag.    | `false`       |
 | `OTEL_LOG_LEVEL`            | Sets the log level. Supported values: `none`, `error`, `warn`, `info`, `debug`. As an alternative to using the environment variable, you can use the `-logLevel` CLI flag. | `info`        |
 
+[^1]: One of `OTEL_GO_AUTO_TARGET_EXE` or `OTEL_GO_AUTO_TARGET_PID` are requried to be set, unless this information is passed directly as CLI arguments.
+
 
 ## Resources