Add missing sample pubspec to workspace

Follow up to https://dart-review.googlesource.com/c/sdk/+/397164

Change-Id: I6c9197bce858cbb7c5af50cf532b0ff1ae7d6311
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/415580
Reviewed-by: Alexander Thomas <[email protected]>
Commit-Queue: Sigurd Meldgaard <[email protected]>

Author: sigurdm

pubspec.yaml

@@ -76,6 +76,7 @@ workspace:
   - pkg/vm_service_protos
   - pkg/vm_snapshot_analysis
   - pkg/wasm_builder
+  - samples/ffi/http
   # dap and language_server_protocol are checked in to and
   # developed in the sdk repo, though they are located in `third_party/`.
   - third_party/pkg/dap

samples/ffi/http/pubspec.yaml

@@ -2,8 +2,10 @@ name: http_sample
 version: 0.0.1
 publish_to: none
 
+resolution: workspace
+
 environment:
-  sdk: '>=3.1.0 <4.0.0'
+  sdk: ^3.5.0
 
 dependencies:
   ffi: ^2.1.0

tools/generate_package_config.dart

@@ -78,6 +78,7 @@ $overrides
       final rootUri = package['rootUri'];
       if (!(rootUri.startsWith('../third_party/') || // Third-party package
               rootUri.startsWith('../pkg/') || // SDK package
+              rootUri.startsWith('../samples/') || // sample package
               rootUri.startsWith('../runtime/') || // VM package
               rootUri.startsWith(
                 '../tools',