ci: split host build into a separate job

.github/workflows/push.yml

@@ -5,6 +5,20 @@ name: ESPurna build
 on: [push, pull_request]
 
 jobs:
+  test:
+    - uses: actions/checkout@v2
+    - uses: actions/setup-python@v2
+      with:
+        python-version: '3.x'
+    - name: Cache PlatformIO
+      uses: actions/cache@v2
+      with:
+        path: ~/.platformio
+        key: ${{ runner.os }}-${{ hashFiles('code/platformio.ini') }}
+    - name: Host tests
+      run: |
+        ./ci_install.sh host
+        ./ci_script.sh host
   build:
     runs-on: ubuntu-latest
     steps:
@@ -12,7 +26,6 @@ jobs:
     - uses: actions/setup-python@v2
       with:
         python-version: '3.x'
-        architecture: x64
     - uses: actions/setup-node@v2
       with:
         node-version: '14'
@@ -26,10 +39,6 @@ jobs:
       with:
         path: ~/.platformio
         key: ${{ runner.os }}-${{ hashFiles('code/platformio.ini') }}
-    - name: Host tests
-      run: |
-        ./ci_install.sh host
-        ./ci_script.sh host
     - name: WebUI tests
       run: |
         ./ci_install.sh webui