add greenmail server to tests github workflow

.github/workflows/tests.yaml

@@ -10,16 +10,15 @@ jobs:
   tests:
     runs-on: ubuntu-latest
     steps:
+      - name: Start GreenMail testing server
+        run: |
+          docker run --rm -d -e GREENMAIL_OPTS='-Dgreenmail.setup.test.all -Dgreenmail.hostname=0.0.0.0 -Dgreenmail.auth.disabled -Dgreenmail.verbose' -p 3025:3025 -p 3110:3110 -p 3143:3143 -p 3465:3465 -p 3993:3993 -p 3995:3995 greenmail/standalone:1.6.2
       - name: Checkout code
         uses: actions/checkout@v2
       - name: Install rust
         uses: actions-rs/toolchain@v1
         with:
             toolchain: stable
-      - name: Check project
-        uses: actions-rs/cargo@v1
-        with:
-          command: check
       - name: Run tests
         uses: actions-rs/cargo@v1
         with: