Update roolup config for ts file

Author: uzair-folio3

packages/optimizely-sdk/rollup.config.js

@@ -43,7 +43,7 @@ const cjsBundleFor = (platform) => ({
     typescript(typescriptPluginOptions),
   ],
   external: ['https', 'http', 'url'].concat(Object.keys(dependencies || {})),
-  input: `lib/index.${platform}.js`,
+  input: `lib/index.${platform}.ts`,
   output: {
     exports: 'named',
     format: 'cjs',