npm run lint: handle Jest correctly

The convention for Jest-based test scripts is to use implicit imports;
ESLint needs to be told about that specifically.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

.eslintrc.json

@@ -1,13 +1,17 @@
 {
   "env": {
     "node": true,
-    "es6": true
+    "es6": true,
+    "jest/globals": true
   },
   "extends": "eslint:recommended",
   "parserOptions": {
     "ecmaVersion": 12,
     "sourceType": "module"
   },
+  "plugins": [
+    "jest"
+  ],
   "rules": {
     "indent": ["error", 4],
     "no-trailing-spaces": "error"

.github/workflows/pr.yml

@@ -6,8 +6,8 @@ jobs:
   check:
     runs-on: ubuntu-latest
     steps:
-      - name: install ESLint
-        run: npm install -g eslint
       - uses: actions/checkout@v3
+      - name: npm install
+        run: npm install
       - name: run ESLint
-        run: eslint -c .eslintrc.json '**/*.js'
+        run: npm run lint