function getInput(name, options) {
    const val = process.env[`INPUT_${name.replace(/ /g, '_').toUpperCase()}`] || '';
    if (options && options.required && !val) {
        throw new Error(`Input required and not supplied: ${name}`);
    }
    if (options && options.trimWhitespace === false) {
        return val;
    }
    return val.trim();
}
Gets the value of an input.
Unless trimWhitespace is set to false in InputOptions, the value is also trimmed.
Returns an empty string if the value is not defined.

@param     name     name of the input to get
@param     options  optional. See InputOptions.
@returns   string