upgrade action's go version

.github/workflows/build_test.yml

 name: gin-vue-admin build test
 
 on:
-    push:
-      branches: 
-        - '*'
-      paths-ignore:
-        - './db/**'
-        - '**.md'
-    pull_request:
-      branches: 
-        - '*'
-      paths-ignore:
-        - './db/**'
-        - '**.md'
+  push:
+    branches:
+      - "*"
+    paths-ignore:
+      - "./db/**"
+      - "**.md"
+  pull_request:
+    branches:
+      - "*"
+    paths-ignore:
+      - "./db/**"
+      - "**.md"
 
 jobs:
   frontend:
-    name: Frontend build 
+    name: Frontend build
     runs-on: ubuntu-latest
     strategy:
       matrix:
         node-version: [12.x]
     steps:
-      
-    - name: Check out branch
-      uses: actions/checkout@v2
+      - name: Check out branch
+        uses: actions/checkout@v2
 
-    - name: Use Node.js ${{ matrix.node-version }}
-      uses: actions/setup-node@v1
-      with:
-        node-version: ${{ matrix.node-version }}
+      - name: Use Node.js ${{ matrix.node-version }}
+        uses: actions/setup-node@v1
+        with:
+          node-version: ${{ matrix.node-version }}
+
+      - name: Build test
+        run: |
+          npm install
+          npm run build
+        working-directory: ./web
 
-    - name: Build test 
-      run: |
-        npm install
-        npm run build
-      working-directory: ./web
-    
   backend:
     name: Backend build
     runs-on: ubuntu-latest
     steps:
+      - name: Set up Go 1.14
+        uses: actions/setup-go@v1
+        with:
+          go-version: 1.14
+        id: go
 
-    - name: Set up Go 1.13
-      uses: actions/setup-go@v1
-      with:
-        go-version: 1.13
-      id: go
-
-    - name: Check out branch
-      uses: actions/checkout@v2
+      - name: Check out branch
+        uses: actions/checkout@v2
 
-    - name: Download dependencies
-      run: |
-        go get -v -t -d ./...
-        if [ -f Gopkg.toml ]; then
-            curl https://raw.githubusercontent.com/golang/dep/master/install.sh | sh
-            dep ensure
-        fi
-      working-directory: ./server
+      - name: Download dependencies
+        run: |
+          go get -v -t -d ./...
+          if [ -f Gopkg.toml ]; then
+              curl https://raw.githubusercontent.com/golang/dep/master/install.sh | sh
+              dep ensure
+          fi
+        working-directory: ./server
 
-    - name: Test and Build
-      run: |
-        go build -v -race
-      working-directory: ./server
\ No newline at end of file
+      - name: Test and Build
+        run: |
+          go build -v -race
+        working-directory: ./server