fix(nix): delegate to shared nix-update-hash action

Replaces the inline workflow with a call to
datum-cloud/actions/.github/workflows/nix-update-hash.yaml@main.

Author: drewr

.github/workflows/nix-update-hash.yaml

@@ -1,50 +1,17 @@
 name: "nix-update-hash"
+
 on:
   push:
     paths:
       - 'go.mod'
       - 'go.sum'
   workflow_dispatch:
 
+permissions:
+  contents: write
+  pull-requests: write
+
 jobs:
   update-hash:
-    runs-on: ubuntu-latest
-    permissions:
-      contents: write
-    steps:
-      - name: Checkout code
-        uses: actions/checkout@v6
-        with:
-          token: ${{ secrets.GITHUB_TOKEN }}
-
-      - name: Install Nix
-        uses: cachix/install-nix-action@v31
-        with:
-          github_access_token: ${{ secrets.GITHUB_TOKEN }}
-
-      - name: Install Go
-        uses: actions/setup-go@v6
-        with:
-          go-version-file: 'go.mod'
-
-      - name: Install Task
-        uses: arduino/setup-task@v2
-
-      - name: Update nix vendor hash
-        run: task nix-update-hash
-
-      - name: Check for changes
-        id: git-check
-        run: |
-          git diff --exit-code flake.nix || echo "changed=true" >> $GITHUB_OUTPUT
-
-      - name: Create Pull Request
-        if: steps.git-check.outputs.changed == 'true'
-        uses: peter-evans/create-pull-request@v7
-        with:
-          token: ${{ secrets.GITHUB_TOKEN }}
-          commit-message: "chore(nix): update vendorHash for go deps"
-          branch: "nix/update-vendorhash"
-          branch-suffix: timestamp
-          title: "chore(nix): update vendorHash for go deps"
-          body: "Automated vendorHash update for Go module dependency changes."
+    uses: datum-cloud/actions/.github/workflows/nix-update-hash.yaml@main
+    secrets: inherit