Give maintainers the ability to remove tags

[jamesjer]

Sometimes an upstream will add a weird git tag, which sorts to the top and blocks subsequent tags from being considered as the newest version. I've had this happen lots of times. When it happens, I add a rule to filter out the weird tag, but it is too late. The new filter does not apply to the already fetched tags, so the weird tag stays at the top.

I just had this happen with the cvc5 project: https://release-monitoring.org/project/268448/. Upstream added tags from the previous cvc4 project, and the higher version numbers for cvc4 are now hiding new releases of cvc5. (That seems like a bug to me, by the way. The cvc4 tags are of the form "cvc4-". They do not contain the string "cvc5" and are also not a bare version number, so why are they considered versions of cvc5?)

Please give maintainers a way to do something about this. For example, give us a button to throw away all fetched tags. Then we can press the "Full Check" button again to refetch the tags and apply any new filters.

In the meantime, if you could do that manually for cvc5, that would be very helpful.

[Zlopez]

It's not that simple as some of the backends doesn't allow to retrieve all the tags back, so removing everything will cause issues. The way we can solve this is to apply the filter retrospectively. I just need to find time to implement that or if somebody will create a pull request I'm OK to merge that.

Regarding the tags, I'm not able to influence the upstream and what tags they add to repository. If they added cvc4- tags to repository the tags will be retrieved until added to filter.

I cleaned the project, which could be done only by admins of the Anitya. Unfortunately we don't have much of them available to watch for incoming flags on the project.