feat: update flutter, dart docs

docs/src/guides/languages/dart_flutter.md

@@ -0,0 +1,36 @@
+---
+icon: simple/flutter
+title: Flutter/Dart
+tags:
+    - Flutter
+    - Dart
+---
+
+<!-- markdownlint-disable single-h1 -->
+# :simple-flutter: Flutter / :simple-dart: Dart
+<!-- markdownlint-enable single-h1 -->
+
+<!-- markdownlint-disable max-one-sentence-per-line -->
+!!! Tip
+    If you're just looking for a complete example,
+    [click here](https://github.com/input-output-hk/catalyst-ci/blob/master/examples/dart/Earthfile).
+    This guide will provide detailed instructions for how the example was built.
+<!-- markdownlint-enable max-one-sentence-per-line -->
+
+This guide will get you started with using the Catalyst CI to build Go-based projects.
+By the end of the guide, we'll have an `Earthfile` that utilizes the Catalyst CI to build, release, and publish our Go program.
+
+To begin, clone the Catalyst CI repository:
+
+```bash
+git clone https://github.com/input-output-hk/catalyst-ci.git
+```
+
+Navigate to `examples/go` to find a very basic Go program which prints "Hello, world!" to the terminal screen using `cowsay`.
+This folder already has an `Earthfile` in it.
+This is the `Earthfile` we will be building in this guide.
+You can choose to either delete the file and start from scratch, or read the guide and follow along in the file.
+
+## TODO
+
+* [ ] [Builders](https://github.com/input-output-hk/catalyst-ci/issues/83)