Add work-in-progress auto-update script

.github/workflows/update.yml

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+name: update casks
+
+on:
+  schedule:
+  - cron: '0 6 * * 6'
+  workflow_dispatch:
+
+jobs:
+  test-bot:
+    runs-on: ubuntu-24.04
+    steps:
+    - uses: actions/checkout@v4
+    - name: Update Casks
+      run: |
+        ./Scripts/update.sh
+    - name: Create Pull Request
+      uses: peter-evans/create-pull-request@v6
+      with:
+        title: 'Update Casks'
+        commit-message: 'Update Casks'

Scripts/.shellcheckrc

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+disable=SC2292
+disable=SC2312

Scripts/update.sh

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+#!/bin/sh
+
+LATEST_VERSION=$(gh api repos/SteamRE/DepotDownloader/releases/latest | jq -r ".name" | sed 's/DepotDownloader[_ ]//')
+CURRENT_VERSION=$(grep 'version "' Casks/depotdownloader.rb | cut -d '"' -f 2)
+
+if [ "${LATEST_VERSION}" = "${CURRENT_VERSION}" ]
+then
+  echo "DepotDownloader Cask is up to date."
+  exit 0
+fi
+
+if [ "$(uname)" = "Darwin" ]
+then
+  SED_INLINE="sed -i .tmp"
+else
+  SED_INLINE="sed -i"
+fi
+
+update_for_arch() {
+  BREW_ARCH=$1
+  FILE_ARCH=$2
+
+  FILE_SHA_256=$(curl -fSsL -o - "https://github.com/SteamRE/DepotDownloader/releases/download/DepotDownloader_${LATEST_VERSION}/DepotDownloader-macos-${FILE_ARCH}.zip" | shasum -a 256 | awk '{print $1}')
+  ${SED_INLINE} "s/${BREW_ARCH}:\([ \t]*\)\"[0-9a-f]*\"/${BREW_ARCH}:\1\"${FILE_SHA_256}\"/g" Casks/depotdownloader.rb
+}
+
+${SED_INLINE} "s/version \"${CURRENT_VERSION}\"/version \"${LATEST_VERSION}\"/" Casks/depotdownloader.rb
+update_for_arch arm arm64
+update_for_arch intel x64
+
+if [ "$(uname)" = "Darwin" ]
+then
+  rm Casks/*.tmp
+fi