ci: migrate release to shared workflows and add PR and autoupdate (#1)

Replace the repo-owned release workflow with the shared go-release workflow.
It must run tests, calculate the version, and call goreleaser with ghcr.io Docker builds.
The release now triggers only on Go, module, Dockerfile, or goreleaser changes.
Add the shared go-pr workflow for pull request checks.
Add the shared go-autoupdate workflow to refresh go.mod and go.sum daily.

.github/workflows/pr.yaml

@@ -0,0 +1,22 @@
+name: Pull Request
+
+on:
+  pull_request:
+    branches:
+      - main
+  push:
+    branches:
+      - "**"
+      - "!main"
+
+permissions:
+  contents: write
+  actions: write
+  pull-requests: write
+  security-events: write
+
+jobs:
+  pr-checks:
+    uses: lukaszraczylo/shared-actions/.github/workflows/go-pr.yaml@main
+    with:
+      go-version: ">=1.24"