fix: added auto-generated line to auto generated dotnet files

src/sdk-auto-generate-dotnet/templates/script.sh

@@ -68,16 +68,36 @@ rm -r $targetDirectory/src
 # remove generated test project
 rm -r $targetDirectory/$packageName.Test
 
-# fix warning in generated code
-# if not already fixed
-
-if ! grep -q ";MSB3245;MSB3243" $projectPath/$packageName.csproj; then
-sed -i '' "s|</Project>|\n\
-  <PropertyGroup>\n\
-    <NoWarn>\$(NoWarn);MSB3245;MSB3243</NoWarn>\n\
-  </PropertyGroup>\n\
-</Project>|g" $projectPath/$packageName.csproj
-fi
+generatedFileHeader="// <auto-generated />
+#pragma warning disable CS8669"
+
+# Prepend $generatedFileHeader to all files in $projectPath/Api
+for file in $(find $projectPath/Api -name '*.cs'); do
+  # skip the ApiClient`.cs file
+  if [[ $file == *ApiClient\`.cs ]]; then
+    continue
+  fi
+  # ensure that the file begins with $generatedFileHeader
+  if ! grep -q "^$generatedFileHeader" $file; then
+    echo "$generatedFileHeader" | cat - $file > temp && mv temp $file
+  fi
+done
+
+# Prepend $generatedFileHeader to all files in $projectPath/Client
+for file in $(find $projectPath/Client -name '*.cs'); do
+  # ensure that the file begins with $generatedFileHeader
+  if ! grep -q "^$generatedFileHeader" $file; then
+    echo "$generatedFileHeader" | cat - $file > temp && mv temp $file
+  fi
+done
+
+# Prepend $generatedFileHeader to all files in $projectPath/Model
+for file in $(find $projectPath/Model -name '*.cs'); do
+  # ensure that the file begins with $generatedFileHeader
+  if ! grep -q "^$generatedFileHeader" $file; then
+    echo "$generatedFileHeader" | cat - $file > temp && mv temp $file
+  fi
+done
 
 # Add generated project to root sln
 dotnet sln $solution add $projectPath/