fix readme

Author: jepiqueau

README.md

@@ -169,7 +169,7 @@ npm install --save @journeyapps/sqlcipher
 npm install --save sqlite3
 npm install --save jszip
 npm install --save node-fetch@2.6.7
-npm install --save @types/sqlite3
+npm install --save-dev @types/sqlite3
 ```
 - **Important**: `node-fetch` version must be `<=2.6.7`; otherwise [you'll get an error](https://github.com/capacitor-community/sqlite/issues/349 "you'll get an error ERR_REQUIRE_ESM") running the app.