add readme under content

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

scripts/mk_nuget_task.py

@@ -91,7 +91,7 @@ def mk_icon(source_root):
 
 def mk_readme(source_root):
     mk_dir("out/content")
-    shutil.copy(f"{source_root}/src/api/dotnet/README.md", "out/README.md")
+    shutil.copy(f"{source_root}/src/api/dotnet/README.md", "out/content/README.md")
 
 
 
@@ -112,6 +112,7 @@ def create_nuget_spec(version, repo, branch, commit, symbols, arch):
         <copyright>&#169; Microsoft Corporation. All rights reserved.</copyright>
         <tags>smt constraint solver theorem prover</tags>
         <icon>content/icon.jpg</icon>
+        <readme>content/README>md</readme>
         <projectUrl>https://github.com/Z3Prover/z3</projectUrl>
         <license type="expression">MIT</license>
         <repository type="git" url="{1}" branch="{2}" commit="{3}" />
@@ -121,6 +122,9 @@ def create_nuget_spec(version, repo, branch, commit, symbols, arch):
             <group targetFramework=".netstandard2.0" />
         </dependencies>
     </metadata>
+    <files>
+      <file src="content/README.md" target="content/README.md"/>
+    </files>
 </package>""".format(version, repo, branch, commit, arch)
     print(contents)
     sym = "sym." if symbols else ""