Update pre_release.yml

on demand

.github/workflows/pre_release.yml

@@ -1,6 +1,7 @@
 name: "pre-release"
 
 on:
+  workflow_dispatch:
   push:
     branches:
       - "dev"
@@ -12,16 +13,20 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
+    
+      - uses: actions/checkout@v2
+      - uses: actions/setup-python@v2
+      - uses: actions/setup-node@v2
+        with:
+          node-version: '16'
 
       - name: Get EMS-ESP source code and version
-        uses: actions/checkout@v2
         id: build_info
         run: |
           version=`grep -E '^#define EMSESP_APP_VERSION' ./src/version.h | awk -F'"' '{print $2}'`
           echo "::set-output name=version::$version"
 
       - name: Install PlatformIO
-        uses: actions/setup-python@v2
         run: |
           python -m pip install --upgrade pip
           pip install -U platformio
@@ -29,9 +34,6 @@ jobs:
           platformio update
 
       - name: Build WebUI
-        uses: actions/setup-node@v2
-        with:
-          node-version: '16'
         run: |
           cd interface
           npm ci