Update default.xml

Add swift-toolchain-sqlite to the toolchain manifest.

Author: compnerd

default.xml

@@ -42,6 +42,7 @@
   <project remote="github" name="apple/swift-syntax" path="swift-syntax" />
   <project remote="github" name="apple/swift-system" path="swift-system" revision="refs/tags/1.3.0" />
   <project remote="github" name="apple/swift-testing" path="swift-testing" />
+  <project remote="github" name="swiftlang/swift-toolchain-sqlite" path="swift-toolchain-sqlite" />
   <project remote="github" name="apple/swift-tools-support-core" path="swift-tools-support-core" />
   <project remote="github" name="apple/swift-xcode-playground-support" path="swift-xcode-playground-support" groups="notdefault" />