make update/verify commands scripts

Signed-off-by: Stephen Gutekanst <stephen@hexops.com>

verify.sh

@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+git diff $(git merge-base origin/main upstream/main)..origin/main \
+    --diff-filter=d \
+    ':(exclude)README.md' \
+    ':(exclude)build.zig' \
+    ':(exclude).github' \
+    ':(exclude).gitignore' \
+    ':(exclude)stub.c'