Prepare v3.26.0

Check whether Flutter SDK version matches the one in package files

Fixes Dart-Code#3540.

Prepare v3.25.1

Prepare v3.25.0

Switch protobuf back to master as null_safety was merged and deleted

Prepare v3.24.2

Prepare v3.24.1

Prepare v3.24.0

Fix detection of workspaces for Create Launch Config command

Prepare v3.23.1