Add VCS to Docker labels

Dockerfile

@@ -25,6 +25,8 @@ LABEL org.label-schema.schema-version="1.0" \
         org.label-schema.name="portal-backend" \
         org.label-schema.description="Java backend for the MIP portal" \
         org.label-schema.url="https://mip.humanbrainproject.eu" \
+        org.label-schema.vcs-type="git" \
+        org.label-schema.vcs-url="https://github.com/LREN-CHUV/portal-backend" \
         org.label-schema.vendor="LREN CHUV" \
         org.label-schema.docker.dockerfile="Dockerfile" \
         org.label-schema.memory-hint="2048"