Change yarn to npm and added dependabot config

Author: lolleko

.github/dependabot.yml

@@ -0,0 +1,8 @@
+version: 2
+updates:
+  - package-ecosystem: 'npm'
+    directory: '/'
+    schedule:
+      interval: 'daily'
+    allow:
+      - dependency-name: 'typescript-to-lua'

.github/workflows/ci.yml

@@ -13,5 +13,5 @@ jobs:
         uses: actions/setup-node@v1
         with:
           node-version: 12
-      - run: yarn --frozen-lockfile
-      - run: yarn lint
+      - run: npm ci
+      - run: npm run lint