Add NPM build script

scripts/npm.ts

@@ -0,0 +1,30 @@
+import { build, emptyDir } from "https://deno.land/x/dnt@0.34.0/mod.ts";
+
+await emptyDir('./npm');
+
+await build({
+  entryPoints: ['./mod.ts'],
+  outDir: './npm',
+  shims: {
+    // see JS docs for overview and more options
+    deno: true,
+  },
+  package: {
+    name: 'strfry-policies',
+    version: Deno.args[0],
+    description: 'Your package.',
+    license: 'Unlicense',
+    repository: {
+      type: 'git',
+      url: 'git+https://gitlab.com/soapbox-pub/strfry-policies.git',
+    },
+    bugs: {
+      url: 'https://gitlab.com/soapbox-pub/strfry-policies/-/issues',
+    },
+  },
+  postBuild() {
+    // steps to run after building and before running the tests
+    Deno.copyFileSync('LICENSE', 'npm/LICENSE');
+    Deno.copyFileSync('README.md', 'npm/README.md');
+  },
+});