ci: split the test.yml workflow into test.yml and lint.yml

Modified test.yml to pull the needed docker images.

Author: rodrigomelo9

.github/workflows/lint.yml

@@ -0,0 +1,19 @@
+name: 'lint'
+
+on:
+  push:
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Install dependencies
+      run: |
+        pip install pycodestyle
+        pip install pylint
+        pip install .
+    - name: Lint
+      run: |
+        pycodestyle fpga examples test
+        pylint fpga

.github/workflows/test.yml

@@ -17,15 +17,15 @@ jobs:
         python-version: ${{ matrix.python-version }}
     - name: Install dependencies
       run: |
-        pip install pycodestyle
-        pip install pylint
         pip install pytest
         pip install .
-    - name: Lint
+    - name: Pull container images
       run: |
-        pycodestyle fpga examples test
-        pylint fpga
-        git diff --check --cached
+        docker pull hdlc/prjtrellis
+        docker pull hdlc/ghdl:yosys
+        docker pull hdlc/icestorm
+        docker pull hdlc/nextpnr:ecp5
+        docker pull hdlc/nextpnr:ice40
     - name: Test
       run: |
         pytest