Update Dockerfile to run apt update before apt install

Change-Id: I9b39a0070cab905623e4faceff2362d6aeae8493
Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>
diff --git a/Dockerfile b/Dockerfile
index 026d471..3846ee0 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -42,7 +42,8 @@
 RUN python3 -m easy_install pip==21.3.1
 RUN pip install tox==3.24.5
 
-RUN DEBIAN_FRONTEND=noninteractive apt-get -y install \
+RUN DEBIAN_FRONTEND=noninteractive apt-get update && \
+    DEBIAN_FRONTEND=noninteractive apt-get -y install \
     libcurl4-openssl-dev \
     libssl-dev \
     wget