Update to use new NIOAtomic over deprecated Atomic

Author: Mordil

Sources/RediStack/RedisConnection.swift

@@ -129,7 +129,7 @@ public final class RedisConnection: RedisClient {
 
     internal let channel: Channel
 
-    private let autoflush = Atomic<Bool>(value: true)
+    private let autoflush: NIOAtomic<Bool> = .makeAtomic(value: true)
     private let _stateLock = Lock()
     private var _state = ConnectionState.open
     private var state: ConnectionState {

Sources/RediStack/RedisMetrics.swift

@@ -59,7 +59,7 @@ public struct RedisMetrics {
 /// A specialized wrapper class for working with `Metrics.Gauge` objects for the purpose of an incrementing or decrementing count of active Redis connections.
 public class ActiveConnectionGauge {
     private let gauge = Gauge(label: .activeConnectionCount)
-    private let count = Atomic<Int>(value: 0)
+    private let count:  NIOAtomic<Int> = .makeAtomic(value: 0)
 
     /// The number of the connections that are currently reported as active.
     var currentCount: Int { return count.load() }