Make release-3.8 buildable

With this change, you can build the branch using `npm ci && npm run
build`.

.gitignore

@@ -83,7 +83,6 @@ tests/cases/user/*/**/*.d.ts
 tests/baselines/reference/dt
 .failed-tests
 TEST-results.xml
-package-lock.json
 tests/cases/user/TypeScript-React-Starter/TypeScript-React-Starter
 tests/cases/user/TypeScript-Node-Starter/TypeScript-Node-Starter
 tests/cases/user/TypeScript-React-Native-Starter/TypeScript-React-Native-Starter

.npmrc

@@ -1 +0,0 @@
-package-lock=false

.travis.yml

@@ -1,7 +1,7 @@
 language: node_js
 
 node_js:
-  - 'node'
+  - '12'
   - '10'
   - '8'
 
@@ -18,7 +18,7 @@ branches:
 
 install:
   - npm uninstall typescript --no-save
-  - npm install
+  - npm ci
 
 cache:
   directories: