Update CHANGELOG to reflect breaking change to PartOfDirective constructor.

pkg/analyzer/CHANGELOG.md

Index: pkg/analyzer/CHANGELOG.md
diff --git a/pkg/analyzer/CHANGELOG.md b/pkg/analyzer/CHANGELOG.md
index 137d374d816996806f8b6a9e9834b1db88fa7466..e7a9e48b5f4b5587380cdeaa6a1642696381a608 100644
--- a/pkg/analyzer/CHANGELOG.md
+++ b/pkg/analyzer/CHANGELOG.md
@@ -1,6 +1,7 @@
 ## 0.30.0-alpha.0
 * Changed the API for creating BazelWorkspace.  It should now be constructed using BazelWorkspace.find().  Note that this might return `null` in the event that the given path is not part of a BazelWorkspace.
 * Added an AST structure to support asserts in constructor initializers (AssertInitializer).  AstVisitor classes must now implement visitAssertInitializer().
+* Changed the API for creating PartOfDirective.  It now accepts a StringLiteral URI, to accomodate "part of" declarations with a URI string rather than a library name.
 
 ## 0.29.0-alpha.0
 * Removed `Element.docRange`.