Merge remote-tracking branch 'upstream/stable' into merge_stable

update version to v1.33.0

support specifying --d-versions ...

Usually you should prefer using configurations and build types, but
sometimes, especially when wrapped in other build tools or when
supporting e.g. different target platforms on the same target
architecture and configuration, you may want to manually manage certain
versions.

checking for duplicates in reverse order ...

cache hits are more likely in the most recent builds

change db filename to "db.json"

add "version" to the cache database

avoid duplicates in cache DB

write cache database Json file

stabilize the cache directory structure

Fix flags Json serialization ...

These flags always appear empty in `dub describe`

update version to v1.33.0-rc.1

update version to v1.33.0-rc.1

update version to v1.33.0-beta.1

Merge remote-tracking branch 'upstream/stable' into merge_stable

update version to v1.32.1

Merge remote-tracking branch 'upstream/stable' into merge_stable

update version to v1.32.1-beta.1

Merge remote-tracking branch 'upstream/stable' into merge_stable

update version to v1.32.0

update version to v1.32.0-rc.1

update version to v1.32.0-rc.1

PackageManager: Store packages hierarchically, by version ...

As explained in the changelog, this hierarchy makes much more sense
than the current one, and will make it possible to read the version
from the directory name.

Merge pull request #2609 from ibuclaw/merge_stable ...

update version to v1.32.0-beta.1

Add unittest to test collection of C sources and headers

update version to v1.32.0-beta.1

Make getDUBExePath returns a NativePath

make build names much smaller (#2589)

Merge remote-tracking branch 'upstream/stable' into merge_stable

update version to v1.31.1

improve warning messages, especially with ~branch (#2585) ...

* improve warning messages, especially with ~branch

* fix single package