Move off of deprecated APIs for package dependencies

[dfed]

Fixes the following warnings:

warning: 'cdp-analytics-swift': /Package.swift:24:10: warning: 'package(url:_:)' is deprecated: use specific requirement APIs instead (e.g. use 'branch:' instead of '.branch')
        .package(url: "https://github.com/segmentio/sovran-swift.git", .exact("1.1.1")),
         ^
/Package.swift:24:73: warning: 'exact' is deprecated
        .package(url: "https://github.com/segmentio/sovran-swift.git", .exact("1.1.1")),
                                                                        ^
/Package.swift:25:10: warning: 'package(url:_:)' is deprecated: use specific requirement APIs instead (e.g. use 'branch:' instead of '.branch')
        .package(url: "https://github.com/segmentio/jsonsafeencoding-swift.git", .exact("2.0.0"))
         ^
/Package.swift:25:83: warning: 'exact' is deprecated
        .package(url: "https://github.com/segmentio/jsonsafeencoding-swift.git", .exact("2.0.0"))
                                                                                  ^

No functional changes.

[Shahroz16]

Thank you for this.!