ci: use dappnode-build-hash reusable workflow

Replaces the inlined build step (which used `--skip_save` and never
posted an IPFS hash on PRs) with a thin caller for the new
`dappnode/workflows/.github/workflows/dappnode-build-hash.yml@master`
reusable workflow. `build.yml` now handles both push and PR events;
`main.yml` is reduced to the release job only.

Also upgrades `actions/checkout` to v7 and adds Node 24 setup for the
release job.

Author: 3alpha

.github/workflows/build.yml

@@ -0,0 +1,12 @@
+name: Build
+
+on:
+  workflow_dispatch:
+  pull_request:
+  push:
+    paths-ignore: ["README.md"]
+
+jobs:
+  build:
+    uses: dappnode/workflows/.github/workflows/dappnode-build-hash.yml@master
+    secrets: inherit

.github/workflows/main.yml

@@ -1,29 +1,24 @@
 name: "Main"
 on:
   repository_dispatch:
-  pull_request:
   push:
     branches:
       - "master"
       - "v[0-9]+.[0-9]+.[0-9]+"
     paths-ignore:
       - "README.md"
+  workflow_dispatch:
 
 jobs:
-  build-test:
-    runs-on: ubuntu-latest
-    name: Build test
-    if: github.event_name != 'push'
-    steps:
-      - uses: actions/checkout@v2
-      - run: npx @dappnode/dappnodesdk build --skip_save
-
   release:
     name: Release
     runs-on: ubuntu-latest
-    if: github.event_name == 'push'
+    if: github.event_name == 'push' || github.event_name == 'repository_dispatch' || github.event_name == 'workflow_dispatch'
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v7
+      - uses: actions/setup-node@v4
+        with:
+          node-version: "24"
       - name: Publish
         run: npx @dappnode/dappnodesdk publish patch --dappnode_team_preset
         env: