DirPath | Multiple:
No | Default: “<Project>/
The path to the project’s directory with source code. PlatformIO uses
it for the pio run command. The default value is
src directory located in the root directory of the project.
This option can also be configured by the global environment variable
This option is useful for people who migrate from Arduino IDE where the source directory should have the same name as the main source file. See example project with own source directory.