Update hashes and add a script to automate that from GitHub artifacts.

update_hashes.sh

@@ -0,0 +1,15 @@
+#!/bin/bash
+
+set -eux
+
+mkdir -p tmp
+
+for OS in macos-10.15 ubuntu-18.04
+do
+  unzip reproduced-$OS.zip -d tmp/reproduced-$OS/
+  tar -C tmp/reproduced-$OS/ -xvf tmp/reproduced-$OS/reproduced.tar
+  cp tmp/reproduced-$OS/reproducible/binaries.sha256sum reproducible/reference_binaries_$OS.sha256sum
+  cp tmp/reproduced-$OS/reproducible/elf2tab.txt reproducible/reference_elf2tab_$OS.txt
+done
+
+rm -R tmp