Update docker base image ubuntu22 and nodejs version18; add README

Change-Id: Ia9eb2627984971e14d8f6afe62d30cf970b29c1b
Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>
diff --git a/Dockerfile b/Dockerfile
index 5aa23bc..869ae70 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -15,14 +15,14 @@
 
 # This Dockerfile is intented for devops and deb package generation
 
-FROM ubuntu:18.04
+FROM ubuntu:22.04
 
 RUN apt-get update && apt-get install -y git build-essential curl \
     && curl -s https://deb.nodesource.com/gpgkey/nodesource.gpg.key | apt-key add - \
-    && echo "deb https://deb.nodesource.com/node_10.x bionic main" | tee -a /etc/apt/sources.list.d/nodesource.list \
-    && echo "deb-src https://deb.nodesource.com/node_10.x bionic main" | tee -a /etc/apt/sources.list.d/nodesource.list \
+    && echo "deb https://deb.nodesource.com/node_18.x jammy main" | tee -a /etc/apt/sources.list.d/nodesource.list \
+    && echo "deb-src https://deb.nodesource.com/node_18.x jammy main" | tee -a /etc/apt/sources.list.d/nodesource.list \
     && apt-get update && apt-get install -y nodejs
-RUN npm install --save @openapi-contrib/json-schema-to-openapi-schema
+#RUN npm install --save @openapi-contrib/json-schema-to-openapi-schema
 RUN npm install -g swagger-cli
 RUN npm install -g speccy