Drop support for Swift 5.0

This is mostly motivated by Swift 5.0 being no longer supported in macos CI (it requires macos 10.14 or earlier).

Author: tsolomko

Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version:5.0
+// swift-tools-version:5.1
 import PackageDescription
 
 let package = Package(

README.md

@@ -1,6 +1,6 @@
 # BitByteData
 
-[![Swift 5.X](https://img.shields.io/badge/Swift-5.X-blue.svg)](https://developer.apple.com/swift/)
+[![Swift 5.1+](https://img.shields.io/badge/Swift-5.1+-blue.svg)](https://developer.apple.com/swift/)
 [![GitHub license](https://img.shields.io/badge/license-MIT-lightgrey.svg)](https://raw.githubusercontent.com/tsolomko/BitByteData/master/LICENSE)
 [![Build Status](https://dev.azure.com/tsolomko/BitByteData/_apis/build/status/tsolomko.BitByteData?branchName=develop)](https://dev.azure.com/tsolomko/BitByteData/_build/latest?definitionId=2&branchName=develop)
 

azure-pipelines.yml

@@ -15,11 +15,6 @@ stages:
   - job: macos
     strategy:
       matrix:
-        macosSwift50:
-          imageName: 'macOS-10.15'
-          DEVELOPER_DIR: '/Applications/Xcode_10.3.app'
-          WATCHOS_ACTIONS: 'clean build'
-          WATCHOS_SIMULATOR: 'Apple Watch Series 4 - 44mm'
         macosSwift51:
           imageName: 'macOS-10.15'
           DEVELOPER_DIR: '/Applications/Xcode_11.3.1.app'
@@ -70,9 +65,6 @@ stages:
   - job: linux
     strategy:
       matrix:
-        linuxSwift50:
-          imageName: 'ubuntu-18.04'
-          containerImage: 'swift:5.0.3-bionic'
         linuxSwift51:
           imageName: 'ubuntu-18.04'
           containerImage: 'swift:5.1.5-bionic'