function parseHeadersInput(inputKey, inputOptions) {
    /** @type {string}*/
    const rawHeadersString = core.getInput(inputKey, inputOptions) || '';
    const headerStrings = rawHeadersString
        .split('\n')
        .map(line => line.trim())
        .filter(line => line !== '');
    return headerStrings
        .reduce((map, line) => {
            const seperator = line.indexOf(':');
            const key = line.substring(0, seperator).trim().toLowerCase();
            const value = line.substring(seperator + 1).trim();
            if (map.has(key)) {
                map.set(key, [map.get(key), value].join(', '));
            } else {
                map.set(key, value);
            }
            return map;
        }, new Map());
}
@param {string} inputKey
@param {any} inputOptions