feat(ci) move linting to its own step

This allows it to run in parallel, and should make the overall run
faster.

.github/workflows/ci.yml

@@ -3,8 +3,8 @@ name: Simple CI
 on: [pull_request]
 
 jobs:
-  linux-build:
-    name: Build Frontend (Linux)
+  lint:
+    name: Lint
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
@@ -20,6 +20,15 @@ jobs:
       run: $(exit $(git status --porcelain --untracked-files=no | head -255 | wc -l)) || (echo "Dirty git tree"; git diff; exit 1)
     - run: npm run lint
     - run: for file in lang/*.json; do npx --yes jsonlint -q $file || exit 1; done
+  linux-build:
+    name: Build Frontend (Linux)
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/setup-node@v1
+      with:
+        node-version: '16.x'
+    - run: npm install
     - run: make
   macos-ci:
     name: Build Frontend (macOS)