Update pygeoapi tag to latest release

Summary

Following some CORS issues identified by @ewojtylko1 and @ahopkins1, we updated pygeoapi to address the issue. We also issued a new release on our fork of pygeoapi to make the fix available while we wait for the upstream PR to get approved. This PR updates the fall back version of the pygeoapi tag to 0.16.dev0+limno.4.beta. In theory there is logic to automatically pull the latest release, but I recall some inconsistency issues where it would not always connect to github and pull the latest release. This updates the fail back version to the latest release so the build pipeline should use the latest release regardless.