Update Dockerfile

Signed-off-by: XhmikosR <xhmikosr@gmail.com>

.devcontainer/Dockerfile

@@ -1,11 +1,14 @@
-FROM node:21-alpine3.19
+FROM node:22-alpine
+
 RUN apk add --no-cache \
-                git \
-                nano\
-                openssh \
-                py3-pip
+    git \
+    nano \
+    openssh \
+    py3-pip
+
 ENV USER node
-USER $USER
+USER ${USER}
+
 # python packages (as mkdocs) are installed in the user's home directory
-# but we need them to be accessible from $PATH
-ENV PATH="$PATH:/home/$USER/.local/bin"
+# but we need them to be accessible from ${PATH}
+ENV PATH="${PATH}:/home/${USER}/.local/bin"