Update default.xml

Update to swift-collections 1.1.6

Author: compnerd

default.xml

@@ -16,7 +16,7 @@
  <project remote="github" name="swiftlang/swift-build" path="swift-build" revision="main" />
  <project remote="github" name="apple/swift-certificates" path="swift-certificates" revision="refs/tags/1.10.1" />
  <project remote="github" name="swiftlang/swift-cmark" path="cmark" revision="gfm" />
- <project remote="github" name="apple/swift-collections" path="swift-collections" revision="refs/tags/1.1.5" />
+ <project remote="github" name="apple/swift-collections" path="swift-collections" revision="refs/tags/1.1.6" />
  <project remote="github" name="swiftlang/swift-corelibs-libdispatch" path="swift-corelibs-libdispatch" />
  <project remote="github" name="swiftlang/swift-corelibs-foundation" path="swift-corelibs-foundation" />
  <project remote="github" name="swiftlang/swift-corelibs-xctest" path="swift-corelibs-xctest" />