ci: add homebrew formula update workflow

Triggers on fork tags (v*-fork*) and uses homebrew-bump-revision to
auto-update the formula in wyattjoh/homebrew-stable.

Author: wyattjoh

.github/workflows/homebrew-update.yml

@@ -0,0 +1,22 @@
+name: Update Homebrew Formula
+
+on:
+  push:
+    tags:
+      - "v*-fork*"
+
+jobs:
+  homebrew:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Update Homebrew formula
+        uses: wyattjoh/homebrew-bump-revision@v1
+        with:
+          tap: wyattjoh/homebrew-stable
+          formula: resticprofile
+          github-token: ${{ secrets.HOMEBREW_GITHUB_TOKEN }}
+          git-user-name: Wyatt Johnson
+          git-user-email: me@wyattjoh.ca