Use different find arg per os

Author: MichaelSimons

tests/Microsoft.DotNet.Docker.Tests/SdkImageTests.cs

@@ -234,7 +234,16 @@ private IEnumerable<SdkContentFileInfo> GetActualSdkContents(ProductImageData im
             {
                 dotnetPath = "/usr/share/dotnet";
                 destinationPath = "/sdk";
-                command = $"find {destinationPath} -type f -o -type l -exec sha512sum {{}} +";
+                
+                // Alpine has limited find syntax support
+                if (imageData.SdkOS.Family == OSFamily.Alpine)
+                {
+                    command = $"find {destinationPath} \\( -type f -o -type l \\) -exec sha512sum {{}} +";
+                }
+                else
+                {
+                    command = $"find {destinationPath} -type f,l -exec sha512sum {{}} +";
+                }
             }
             else
             {