IMF/WEO: missing series in last publication

Context

The WEO dataset is published twice a year, in April and October. Because of the current global economic conditions, last month's publication was very limited and contained only 8 weo codes instead of 45 in October 2019.

Due to how DBnomics operates, only the series from the last update of the provider are published in DBnomics UI & API. However, the other series are still relevant to the DBnomics users, they just weren't updated this time by the provider. As such, they should be available in DBnomics.

Possible solutions

Previous technical solutions for this type of situation used a repository-wide approach with Git to change the way the data is updated. But in this case the situation only affects one dataset of the fetcher. It could be cumbersome and not satisfactory to apply this type of solution to all the datasets of the IMF.

Another solution could be to merge this limited April update with the last comprehensive update (October's) in order to have the best of both worlds.

@thomasbrand @MichelJuillard What would be preferable from the users' point of view?