Update default.xml

Update swift-subprocess to 0.2.1

Author: compnerd

default.xml

@@ -42,7 +42,7 @@
  <project remote="github" name="apple/swift-numerics" path="swift-numerics" groups="notdefault" />
  <project remote="github" name="swiftlang/swift-package-manager" path="swift-package-manager" />
  <project remote="github" name="apple/swift-protobuf" path="swift-protobuf" groups="notdefault" />
- <project remote="github" name="swiftlang/swift-subprocess" path="swift-subprocess" revision="refs/tags/0.2" />
+ <project remote="github" name="swiftlang/swift-subprocess" path="swift-subprocess" revision="refs/tags/0.2.1" />
  <project remote="github" name="swiftlang/swift-syntax" path="swift-syntax" />
  <project remote="github" name="apple/swift-system" path="swift-system" revision="refs/tags/1.5.0" />
  <project remote="github" name="swiftlang/swift-testing" path="swift-testing" />