build: Check-in Cargo.lock files and lockdown .net (#384)

Use frozen and locked builds

Signed-off-by: Anand Krishnamoorthi <anakrish@microsoft.com>

bindings/csharp/global.json

@@ -0,0 +1,10 @@
+{
+    "msbuild-sdks": {
+      "Microsoft.Build.NoTargets": "3.7.56"
+    },
+    "sdk": {
+      "allowPrerelease": false,
+      "version": "8.0.407",
+      "rollForward": "disable"
+    }
+}