Only generate setters and getters for public properties (#47)

* Only generate setters and getters for public properties

* .

tests/ProxyInterfaceSourceGeneratorTests/Source/IMixedVisibility.cs

@@ -0,0 +1,5 @@
+namespace ProxyInterfaceSourceGeneratorTests.Source;
+
+public partial interface IMixedVisibility
+{
+}

tests/ProxyInterfaceSourceGeneratorTests/Source/MixedVisibility.cs

@@ -0,0 +1,6 @@
+namespace ProxyInterfaceSourceGeneratorTests.Source;
+
+public class MixedVisibility
+{
+    public string Foo { get; protected set; } //<- this will generate bad code
+}