Add watchOS deployment to PodSpec build script (#110)
Add watchOS deployment to PodSpec build script (#110)

Motivation:

We support watchOS 6+ with SwiftNIO Transport Services; as such we should
include watchOS as a deployment target for our CocoaPods.

Modifications:

- Add a watchOS deployment target to `build_podspecs.sh`

Result:

Users can deploy to watchOS 6+ with CocoaPods.
apple/swift-nio-extras,apple/swift-nio-extras,apple/swift-nio-extras,apple/swift-nio-extras