Defer error message generation to the end of the dependency resolution process.

Put a hard limit in the number of dependency resolution iterations. ...

This avoids the process getting stuck in the resolution phase "indefinitely", so that for example CI runs don't get stuck anymore. It also communicates the problem and potential resolutions more clearly. If the DUB_NO_RESOLVE_LIMIT environment variable is set, the resolution process will run without this limit.

Small optimizations in DependencyResolver.

Cache the result of DependencyVersionResolver.getChildren.

Avoid GC allocations in DependencyVersionResolver.getChildren.

Optimize Dependency.merge. ...

Reduces the amount of version comparisons.

Optimize Dependency.toHash/matchesAny.

Add pure/nogc annotations to the SemVer module.

Optimization: avoid UTF decoding in the semver module. ...

SemVer operates on ASCII only, so there is no need to perform any decoding.

Don't weaken the selected log level for "dub describe".

Merge pull request #1193 from dlang/registry_skip_configured ...

Add SkipPackageSuppliers.configured and fix unit test.
merged-on-behalf-of: Sönke Ludwig <s-ludwig@users.noreply.github.com>

Improve command line documentation for --skip-registry.

Add SkipPackageSuppliers.configured and fix unit test. ...

With only .all and .standard, an intermediate option was missing to make the unit test pass on systems with additional registries configured in the DUB configuration.

Perform package linting only for packages in the current project.

Fix recursive package validation.

Merge pull request #1285 from dlang/fix_latest_dmd ...

[trivial] Fix serialization unit test for DMD 2.077.0.
merged-on-behalf-of: Sönke Ludwig <s-ludwig@users.noreply.github.com>

Merge pull request #1279 from MartinNowak/merge_stable ...

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

Merge pull request #1246 from wilzbach/more-fallbacks ...

Use multiple registry fallbacks instead of one

Fix serialization unit test for DMD 2.077.0.

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

update version to v1.6.0

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

update version to v1.6.0-rc.1

Merge pull request #1273 from MartinNowak/merge_stable ...

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

Merge pull request #1194 from dlang/warn_wrong_sub_configs ...

Output a warning for sub configurations that have no effect.
merged-on-behalf-of: Sönke Ludwig <s-ludwig@users.noreply.github.com>

update version to v1.6.0-beta.2

update changelog and version for v1.6.0-beta.1

Use logDebug instead of assert(1)

Hide enums from public API.

Refactor determinePlatform, determineArchitecture, and determineCompiler from dub.platform into strings that can be pasted into generatePlatformProbeFile and remove unused imports.