[CHANGELOG] Add notes on build.rs symbol scraping changes

Change-Id: I5fcb133b29ff7d5821c46b248f5e97dec29e4f65
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 805a678..0833fd9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,6 +16,10 @@
 - `public::rsa` now supports RSA-PKCS1v1.5 signing (behind the `rsa-pkcs1v15`
   feature flag).
 
+### Changed
+- `build.rs` implements symbol name scraping natively, and no longer relies on
+  BoringSSL's `read_symbols.go`.
+
 ### Fixed
 - `build.rs` no longer respects `$GOPATH`, instead it always uses the
   `go.mod` from the vendored boringssl.