eslint@9, prettier (#105)

* Update build.yml to allow pushes to any branch

Remove branch restriction for push events, which prevents forked projects from running CI checks prior to creating a PR.

* eslint, prettier config only

prettier.config.mjs

@@ -0,0 +1,13 @@
+export default {
+  arrowParens: 'avoid',
+  bracketSpacing: true,
+  endOfLine: 'auto',
+  jsxBracketSameLine: false,
+  jsxSingleQuote: true,
+  plugins: ['prettier-plugin-tailwindcss'],
+  printWidth: 80,
+  semi: false,
+  singleQuote: true,
+  tabWidth: 2,
+  trailingComma: 'all',
+}