Get OpenVPN version automatically

.drone.yml

@@ -22,6 +22,8 @@ steps:
       CONTAINERFILE: ./containerfiles/Containerfile-XOR
     commands:
       - source ./env/openvpn_xor.env
+      - git clone https://github.com/Tunnelblick/Tunnelblick.git /tmp/tunnelblick
+      - export OPENVPN_VERSION=$(ls /tmp/tunnelblick/third_party/openvpn | sed 's/openvpn-//g' | sort  -k1,1nr -k2,2n -k3,3n | head -n 1)
       - export CUSTOM_TAG="v$OPENVPN_VERSION-XOR-$TUNNELBLICK_VERSION"
       - export BUILD_ARGS="--build-arg OPENVPN_VERSION=$OPENVPN_VERSION --build-arg TUNNELBLICK_VERSION=$TUNNELBLICK_VERSION"
       - build-container

env/openvpn_xor.env

@@ -1,2 +1 @@
-export OPENVPN_VERSION=2.6.9
 export TUNNELBLICK_VERSION=4.0.0beta15