Switch build target to browser and bump version to 2.1.1

Updated the build target from Node to browser in `build.ts` to support browser environments. Incremented the package version from 2.1.0 to 2.1.1 to reflect the change.

build.ts

@@ -4,10 +4,10 @@ import isolatedDecl from 'bun-plugin-isolated-decl';
 await Bun.build({
   entrypoints: ['./src/index.ts', './src/types.ts'],
   outdir: './dist',
-  target: 'node',
+  target: 'browser',
   plugins: [
     isolatedDecl({
       forceGenerate: true,  // Generate declaration files even if there are errors
     })
   ],
-});
+});