Some fixes and tweaks to Connect (npgsql#3234)

* Use Path.IsPathRooted to detect Unix domain sockets in async
* Apply fake timeout to async DNS lookup

v4.1.5

Toggle v4.1.5's commit message

Merge branch 'hotfix/4.1.5' into HEAD

v4.1.4

Toggle v4.1.4's commit message

Merge branch 'hotfix/4.1.4' into stable

v4.0.11

Toggle v4.0.11's commit message

Remove <PackageIconUrl>

v5.0.0-alpha1

Toggle v5.0.0-alpha1's commit message

Set version to 5.0.0-alpha1

v4.1.3.1

Toggle v4.1.3.1's commit message

Bump version to 4.1.3.1

v4.1.3

Toggle v4.1.3's commit message

Merge branch 'hotfix/4.1.3'

v4.1.2

Toggle v4.1.2's commit message

Merge branch 'hotfix/4.1.2'

v4.1.1

Toggle v4.1.1's commit message

Merge branch 'hotfix/4.1.1'

v4.1.0

Toggle v4.1.0's commit message

Merge branch 'release/4.1'