[dev.boringcrypto.go1.12] all: merge go1.12.13 into dev.boringcrypto.go1.12

Change-Id: I5f6cae0a2ae30cd031e1abdeee4dbad9f4facd00
diff --git a/doc/devel/release.html b/doc/devel/release.html
index d136cc9..7cfac9d 100644
--- a/doc/devel/release.html
+++ b/doc/devel/release.html
@@ -119,6 +119,13 @@
 1.12.12 milestone</a> on our issue tracker for details.
 </p>
 
+<p>
+go1.12.13 (released 2019/10/31) fixes an issue on macOS 10.15 Catalina
+where the non-notarized installer and binaries were being
+<a href="https://golang.org/issue/34986">rejected by Gatekeeper</a>.
+Only macOS users who hit this issue need to update.
+</p>
+
 <h2 id="go1.11">go1.11 (released 2018/08/24)</h2>
 
 <p>