chore: add missing steps to package and publish jobs

Author: marcusrbrown

.github/workflows/ci.yml

@@ -28,6 +28,9 @@ jobs:
     runs-on: ubuntu-latest
     needs: build
     steps:
+      - uses: actions/checkout@v2
+      - name: Install dependencies
+        run: npm ci
       - name: Package extension
         uses: lannonbr/vsce-action@master
         with:
@@ -47,6 +50,9 @@ jobs:
     runs-on: ubuntu-latest
     needs: build
     steps:
+      - uses: actions/checkout@v2
+      - name: Install dependencies
+      - run: npm ci
       - name: Publish extension
         uses: lannonbr/vsce-action@master
         with: