fix: upgrade rollup-plugin-sourcemaps from 0.6.1 to 0.6.2 (#12)

Snyk has created this PR to upgrade rollup-plugin-sourcemaps from 0.6.1 to 0.6.2.

See this package in NPM:
https://www.npmjs.com/package/rollup-plugin-sourcemaps

See this project in Snyk:
https://app.snyk.io/org/wallace41290/project/948d3534-f195-42f8-b20c-055729fc9646?utm_source=github&utm_medium=upgrade-pr

package.json

@@ -84,7 +84,7 @@
     "rollup-plugin-commonjs": "^9.1.8",
     "rollup-plugin-json": "^3.1.0",
     "rollup-plugin-node-resolve": "^3.4.0",
-    "rollup-plugin-sourcemaps": "^0.6.1",
+    "rollup-plugin-sourcemaps": "^0.6.2",
     "rollup-plugin-typescript2": "^0.27.1",
     "semantic-release": "^17.0.7",
     "shelljs": "^0.8.3",