community/miniflux: upgrade to 2.0.49

The release notes introduce three new configuration variables: LOG_FORMAT, LOG_LEVEL, and LOG_FILE. These default to text, info, and stderr, respectively. These sound reasonable to me, but if others disagree we can set them in the package's miniflux.conf. We already do this for LOG_DATE_TIME (setting it to yes) because its default value was deemed undesirable.