docs: update README

Author: marcelblijleven

README.md

@@ -1,5 +1,5 @@
 # Advent of Code ⭐️
-[![Stars collected](https://shields.io/static/v1?label=stars%20collected&message=171&color=yellow)]()
+[![Stars collected](https://shields.io/static/v1?label=stars%20collected&message=173&color=yellow)]()
 [![codecov](https://codecov.io/gh/marcelblijleven/adventofcode/branch/master/graph/badge.svg?token=jZ2TgfyltM)](https://codecov.io/gh/marcelblijleven/adventofcode)
 [![tests](https://github.com/marcelblijleven/adventofcode/actions/workflows/tests.yaml/badge.svg)](https://github.com/marcelblijleven/adventofcode)
 [![version](https://img.shields.io/github/v/release/marcelblijleven/adventofcode.svg)](https://github.com/marcelblijleven/adventofcode/releases)
@@ -161,6 +161,7 @@ Collection of my Advent of Code solutions in an overkill project setup 👻🎄.
 | 06 | ⭐️ | ⭐️ |
 | 07 | ⭐️ | ⭐️ |
 | 08 | ⭐️ | ⭐️ |
+| 09 | ⭐️ | ⭐️ |
 
 </p>
 </details>

image_dark.svg

@@ -1,5 +1,5 @@
 # 2023
-Solutions for 8 days in 2023 with a total of 16 stars collected
+Solutions for 9 days in 2023 with a total of 18 stars collected
 
 | day   | part one | part two |
 | :---: | :------: | :------: |
@@ -10,4 +10,5 @@ Solutions for 8 days in 2023 with a total of 16 stars collected
 | 05 | ⭐️ | ⭐️ |
 | 06 | ⭐️ | ⭐️ |
 | 07 | ⭐️ | ⭐️ |
-| 08 | ⭐️ | ⭐️ |
+| 08 | ⭐️ | ⭐️ |
+| 09 | ⭐️ | ⭐️ |