docs: add doc on how to upgrade hugo

README.md

@@ -17,3 +17,19 @@ The blog is hosted on AWS using the following services:
 On new commits, a GitHub Action job will deploy the new infrastructure via Terraform (if any changes were detected), build the Hugo website and deploy its content to AWS S3 (again, if new changes are detected).
 
 ![Automatic deploy static website AWS drawio](https://github.com/antoinedelia/cloud-antoine-delia/assets/7138350/d0878545-22f1-42c8-8b04-aca4a932aaee)
+
+## Upgrade
+
+### Hugo
+
+To upgrade Hugo, edit the `main.yml` file with [hugo's latest release](https://github.com/gohugoio/hugo/releases):
+```yml
+# Replace this URL with a newer version
+- run: sudo wget https://github.com/gohugoio/hugo/releases/download/v0.133.1/hugo_extended_0.133.1_linux-amd64.deb -O hugo.deb
+```
+
+Make sure to update the hugo's theme as well:
+```sh
+git submodule init
+git submodule update --remote --merge
+```