Add ESP32-C3 build workflow and badge to README

Agent-Logs-Url: https://github.com/FastLED/fbuild/sessions/33823d4e-3a31-4b18-af7a-647a27f8f643

Co-authored-by: zackees <6856673+zackees@users.noreply.github.com>

Author: Copilot

.github/workflows/build-esp32c3.yml

@@ -0,0 +1,16 @@
+name: Build ESP32-C3
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  build:
+    uses: ./.github/workflows/template_build.yml
+    with:
+      workflow-name: "ESP32-C3"
+      test-dir: "tests/esp32c3"
+      env-name: "esp32c3"
+      firmware-ext: "bin"

README.md

@@ -13,6 +13,7 @@
 ### ESP32
 [![Build ESP32 Dev](https://github.com/fastled/fbuild/actions/workflows/build-esp32dev.yml/badge.svg)](https://github.com/fastled/fbuild/actions/workflows/build-esp32dev.yml)
 [![Build ESP32-C2](https://github.com/fastled/fbuild/actions/workflows/build-esp32c2.yml/badge.svg)](https://github.com/fastled/fbuild/actions/workflows/build-esp32c2.yml)
+[![Build ESP32-C3](https://github.com/fastled/fbuild/actions/workflows/build-esp32c3.yml/badge.svg)](https://github.com/fastled/fbuild/actions/workflows/build-esp32c3.yml)
 [![Build ESP32-C6](https://github.com/fastled/fbuild/actions/workflows/build-esp32c6.yml/badge.svg)](https://github.com/fastled/fbuild/actions/workflows/build-esp32c6.yml)
 [![Build ESP32-S3](https://github.com/fastled/fbuild/actions/workflows/build-esp32s3.yml/badge.svg)](https://github.com/fastled/fbuild/actions/workflows/build-esp32s3.yml)