let's use current ubuntu and not eol :)

.drone.yml

@@ -7,11 +7,15 @@ clone:
 
 steps:
 
+- name: submodules
+  image: alpine/git
+  commands:
+  - git submodule update --recursive --remote
+
 - name: coverage
-  image: ubuntu:19.10
+  image: ubuntu:20.04
   commands:
   - apt-get update && apt-get install -y \
       build-essential cmake pkg-config libboost-all-dev \
       libssl-dev libzmq3-dev libunbound-dev libsodium-dev libpgm-dev make git
   - make coverage
-