NFC: Add a CHANGELOG.md entry about cyclic package-level dependencies

Author: xedin

CHANGELOG.md

@@ -1,5 +1,11 @@
 Note: This is in reverse chronological order, so newer entries are added to the top.
 
+* [#7530]
+
+  Makes it possible for packages to depend on each other if such dependence doesn't form any target-level cycles. For example,
+  package `A` can depend on `B` and `B` on `A` unless targets in `B` depend on products of `A` that depend on some of the same
+  targets from `B` and vice versa.
+
 Swift 6.0
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