Update drone.yml

drone.yml

 - name: build
   image: debian:stable-slim
   privileged: false
-  cache:
-    - /var/cache/apt
   environment:
-    DEBUG: true
+    MAKEFLAGS="-j 4"
   commands:
-    - export PATH=$PATH
     - echo 'Acquire::http { Proxy "http://unino.de:3142"; }' | tee -a /etc/apt/apt.conf.d/proxy
-    - ls -l /var/cache/apt
     - apt-get update
     - apt-get --yes upgrade
     - apt-get --yes install build-essential libc6-dev libhidapi-dev libssl-dev
+    - export MAKEFLAGS=$MAKEFLAGS 
     - cd src && make 
     - cd contrib && make 
     - cd .. ; ls -l radangel contrib/websockify ; md5sum radangel contrib/websockify ; cd ..