Add mapping for sy:updatePeriod and sy:updateFrequency

[w3stling]

Map sy:updatePeriod and sy:updateFrequency to Channel::getTtl()

<rss xmlns:sy="http://purl.org/rss/1.0/modules/syndication/">
    <channel>
    ...
        <sy:updatePeriod>hourly</sy:updatePeriod>
        <sy:updateFrequency>2</sy:updateFrequency>
    ...
</rss>

[github-actions[bot]]

Test Results

 11 files   11 suites   35s :stopwatch: 286 tests 284 :white_check_mark: 2 :zzz: 0 :x: 294 runs  292 :white_check_mark: 2 :zzz: 0 :x:

Results for commit ae5f96bf.

:recycle: This comment has been updated with latest results.

[sonarcloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud