fix: Improve the default User-agent string. (#10606)

...presets/bitbucket-server/__snapshots__/index.spec.ts.snap

...config/presets/bitbucket/__snapshots__/index.spec.ts.snap

lib/config/presets/gitea/__snapshots__/index.spec.ts.snap

lib/config/presets/github/__snapshots__/index.spec.ts.snap

lib/config/presets/gitlab/__snapshots__/index.spec.ts.snap

...atasource/bitbucket-tags/__snapshots__/index.spec.ts.snap

lib/datasource/cdnjs/__snapshots__/index.spec.ts.snap

lib/datasource/clojure/__snapshots__/index.spec.ts.snap

lib/datasource/crate/__snapshots__/index.spec.ts.snap

lib/datasource/dart/__snapshots__/index.spec.ts.snap

lib/datasource/docker/__snapshots__/index.spec.ts.snap

...source/galaxy-collection/__snapshots__/index.spec.ts.snap

lib/datasource/galaxy/__snapshots__/index.spec.ts.snap

...tasource/github-releases/__snapshots__/index.spec.ts.snap

lib/datasource/github-tags/__snapshots__/index.spec.ts.snap

lib/datasource/gitlab-tags/__snapshots__/index.spec.ts.snap

lib/datasource/go/__snapshots__/index.spec.ts.snap

...atasource/gradle-version/__snapshots__/index.spec.ts.snap

lib/datasource/helm/__snapshots__/index.spec.ts.snap

lib/datasource/hex/__snapshots__/index.spec.ts.snap