Support downloading/publishing artifacts from Pipelines endpoint (#188)

* Support downloading/publishing artifacts from Pipelines endpoint
* Remove `Path` from everywhere
* Remove unused JobId argument
* PR feedback
* More PR feedback

src/Sdk/PipelinesWebApi/UnknownEnum.cs

@@ -0,0 +1,45 @@
+using System;
+using System.Linq;
+using System.Runtime.Serialization;
+
+namespace GitHub.Actions.Pipelines.WebApi
+{
+    public static class UnknownEnum
+    {
+        public static T Parse<T>(string stringValue)
+        {
+            return (T)Parse(typeof(T), stringValue);
+        }
+
+        public static object Parse(Type enumType, string stringValue)
+        {
+            var underlyingType = Nullable.GetUnderlyingType(enumType);
+            enumType = underlyingType != null ? underlyingType : enumType;
+
+            var names = Enum.GetNames(enumType);
+            if (!string.IsNullOrEmpty(stringValue))
+            {
+                var match = names.FirstOrDefault(name => string.Equals(name, stringValue, StringComparison.OrdinalIgnoreCase));
+                if (match != null)
+                {
+                    return Enum.Parse(enumType, match);
+                }
+
+                // maybe we have an enum member with an EnumMember attribute specifying a custom name
+                foreach (var field in enumType.GetFields())
+                {
+                    var enumMemberAttribute = field.GetCustomAttributes(typeof(EnumMemberAttribute), false).FirstOrDefault() as EnumMemberAttribute;
+                    if (enumMemberAttribute != null && string.Equals(enumMemberAttribute.Value, stringValue, StringComparison.OrdinalIgnoreCase))
+                    {
+                        // we already have the field, no need to do enum.parse on it
+                        return field.GetValue(null);
+                    }
+                }
+            }
+
+            return Enum.Parse(enumType, UnknownName);
+        }
+
+        private const string UnknownName = "Unknown";
+    }
+}