fix: use latest NodeSource installation script

because with the previous method,
we were getting the following error:

```console
 > [web production 13/17] RUN npm install -D mjml@"^4.14.1":
0.088 /bin/sh: 1: npm: not found
```

See the following for more details:

- nodesource/distributions#1770 (comment)
- nodesource/distributions#1601 (comment)

{{cookiecutter.project_slug}}/Dockerfile

@@ -60,11 +60,8 @@ RUN apt-get update --yes --quiet && apt-get install --yes --quiet --no-install-r
     && apt-get clean
 
 # Install node (Keep the version in sync with the node container above)
-RUN mkdir -p /etc/apt/keyrings
-RUN curl -fsSL https://deb.nodesource.com/gpgkey/nodesource-repo.gpg.key | gpg --dearmor -o /etc/apt/keyrings/nodesource.gpg
-RUN echo "deb [signed-by=/etc/apt/keyrings/nodesource.gpg] https://deb.nodesource.com/node_${NODE_MAJOR}.x nodistro main" | tee /etc/apt/sources.list.d/nodesource.list
-RUN apt-get update
-RUN apt install nodejs -y
+RUN curl -fsSL https://deb.nodesource.com/setup_${NODE_MAJOR}.x | bash - && \
+    apt-get install -y nodejs
 
 # Use user "wagtail" to run the build commands below and the server itself.
 USER wagtail