Merge #12850: doc: add qrencode to brew install instructions

0314ad4 doc: add qrencode to brew install instructions (buddilla)

Pull request description:

  Build was missing qr code(qrencode libs) support and brew team no longer supports anything less than macOS 10.11

Tree-SHA512: 1bc22f02e64f0db0730180ca97fba17c7ad05c9d81c60d1b0d029196d5141e691e524d2df2be1fb89852076f3a252da69bb117042cbd08985b89954432692529

Author: laanwj

doc/build-osx.md

@@ -16,7 +16,7 @@ Then install [Homebrew](https://brew.sh).
 Dependencies
 ----------------------
 
-    brew install automake berkeley-db4 libtool boost miniupnpc openssl pkg-config protobuf python qt libevent
+    brew install automake berkeley-db4 libtool boost miniupnpc openssl pkg-config protobuf python qt libevent qrencode
 
 See [dependencies.md](dependencies.md) for a complete overview.