Very slow propagation of registry updates in Julia v1.5

Our build on Julia v1.5 started failing due to unavailable/invisible new versions of dependent packages.

For example: https://travis-ci.org/github/pevnak/Mill.jl

Mill.jl depends on HierarchicalUtils.jl, which got new version 1.0.0 yesterday. All Julia v1.4 tests succeed, however, all v1.5 tests fail due to unavailable latest version of HierarchicalUtils.jl.

The same happens here: https://travis-ci.org/github/Pevnak/JsonGrinder.jl

JsonGrinder.jl depends on Mill.jl this time, however, the newest version is not available in all v1.5 tests.

Tested locally on Julia v1.5.0-rc1 and there are no issues, it’s happening only in Travis. Maybe related to: https://github.com/JuliaRegistries/General/issues/16777

@ararslan
@staticfloat

@StefanKarpinski

Can we used the same workaround as implemented in GitHub Actions?