Raise the minimum deployment target to 10.11 (#3384)

rdar://76035286

Author: neonichu

Sources/PackageModel/Platform.swift

@@ -25,7 +25,7 @@ public struct Platform: Equatable, Hashable, Codable {
         self.oldestSupportedVersion = oldestSupportedVersion
     }
 
-    public static let macOS: Platform = Platform(name: "macos", oldestSupportedVersion: "10.10")
+    public static let macOS: Platform = Platform(name: "macos", oldestSupportedVersion: "10.11")
     public static let iOS: Platform = Platform(name: "ios", oldestSupportedVersion: "9.0")
     public static let tvOS: Platform = Platform(name: "tvos", oldestSupportedVersion: "9.0")
     public static let watchOS: Platform = Platform(name: "watchos", oldestSupportedVersion: "2.0")

Tests/BuildTests/BuildPlanTests.swift

@@ -20,7 +20,7 @@ import XCTest
 
 let hostTriple = Resources.default.toolchain.triple
 #if os(macOS)
-    let defaultTargetTriple: String = hostTriple.tripleString(forPlatformVersion: "10.10")
+    let defaultTargetTriple: String = hostTriple.tripleString(forPlatformVersion: "10.11")
 #else
     let defaultTargetTriple: String = hostTriple.tripleString
 #endif