feat: add workflow to create and push pkg Go module version tags (#5001)

* Initial plan

* feat: add workflow to create and push pkg version tags

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Co-authored-by: sweatybridge <1639722+sweatybridge@users.noreply.github.com>

* feat: add version validation and tag existence check to tag-pkg workflow

Agent-Logs-Url: https://github.com/supabase/cli/sessions/78b5dd93-1c78-4cdc-b6f0-c664080934b8

Co-authored-by: sweatybridge <1639722+sweatybridge@users.noreply.github.com>

* Apply suggestion from @Copilot

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: sweatybridge <1639722+sweatybridge@users.noreply.github.com>
Co-authored-by: Han Qiao <sweatybridge@gmail.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: 3 people

.github/workflows/tag-pkg.yml

@@ -0,0 +1,37 @@
+name: Tag pkg
+
+on:
+  workflow_dispatch:
+    inputs:
+      version:
+        description: "pkg version to tag (e.g. v1.2.2)"
+        required: true
+        type: string
+
+permissions:
+  contents: write
+
+jobs:
+  tag:
+    name: Create pkg tag
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          ref: develop
+          fetch-depth: 0
+
+      - name: Create and push pkg tag
+        run: |
+          VERSION="${{ inputs.version }}"
+          if ! [[ "$VERSION" =~ ^v(0|[1-9][0-9]*)\.(0|[1-9][0-9]*)\.(0|[1-9][0-9]*)$ ]]; then
+            echo "Error: version '$VERSION' does not match semver format (e.g. v1.2.2)"
+            exit 1
+          fi
+          TAG="pkg/$VERSION"
+          if git rev-parse "$TAG" >/dev/null 2>&1; then
+            echo "Error: tag '$TAG' already exists"
+            exit 1
+          fi
+          git tag "$TAG"
+          git push origin "$TAG"