Add build:types to GitHub build workflow.

The package.json already had a "types" key. So by adding the build:types
to the workflow, the next released version of hls.js will have a
hls.d.ts.

Author: itsjamie

.github/workflows/build.yml

@@ -80,7 +80,7 @@ jobs:
 
       - name: build
         run: |
-          npm run type-check
+          npm run build:types
           npm run build
           npm run docs
           # check that hls.js doesn't error if requiring in node