Dockerfile: added git

git is required for CICD, specifically for devops/tools/generatechangelog-pipeline.sh

Change-Id: If30ea27fb2058bbcc450aa1ee2b45385839be8df
Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>
diff --git a/Dockerfile b/Dockerfile
index b740f2a..2760e73 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -17,7 +17,7 @@
 
 FROM ubuntu:18.04
 
-RUN apt-get update && apt-get install -y build-essential nodejs npm
+RUN apt-get update && apt-get install -y git build-essential nodejs npm
 RUN npm install -g swagger-cli
 RUN npm install -g speccy