Update min version of grpc-swift to fix static Linux SDK build

Author: gjcairo

Package.swift

@@ -43,7 +43,7 @@ let products: [Product] = [
 let dependencies: [Package.Dependency] = [
   .package(
     url: "https://github.com/grpc/grpc-swift.git",
-    from: "2.0.0"
+    from: "2.1.1"
   ),
   .package(
     url: "https://github.com/grpc/grpc-swift-protobuf.git",