Install requirements via install script

Closes coop-cloud/abra#196.

.drone.yml

@@ -3,21 +3,29 @@ kind: pipeline
 name: linters
 steps:
   - name: run shellcheck
-    image: koalaman/shellcheck-alpine:v0.7.1
+    image: koalaman/shellcheck-alpine
     commands:
       - shellcheck abra
       - shellcheck bin/*.sh
+      - shellcheck deploy/install.abra.coopcloud.tech/installer
 
   - name: run flake8
-    image: alpine/flake8:3.9.0
+    image: alpine/flake8
     commands:
-      - flake8 --max-line-length 100 bin/app-json.py
+      - flake8 --max-line-length 100 bin/*.py
 
   - name: run unit tests
     image: decentral1se/docker-dind-bats-kcov
     commands:
       - bats tests
 
+  - name: test installation script
+    image: debian:buster
+    commands:
+      - apt update && apt install -yqq sudo lsb-release
+      - deploy/install.abra.coopcloud.tech/installer --no-prompt
+      - ~/.local/bin/abra version
+
   - name: publish image
     image: plugins/docker
     settings:
@@ -31,6 +39,7 @@ steps:
       - run shellcheck
       - run flake8
       - run unit tests
+      - test installation script
     when:
       event:
         exclude:
@@ -49,6 +58,7 @@ steps:
       - run shellcheck
       - run flake8
       - run unit tests
+      - test installation script
       - publish image
     when:
       event:
@@ -67,6 +77,7 @@ steps:
       - run shellcheck
       - run flake8
       - run unit tests
+      - test installation script
       - publish image
       - trigger downstream builds
     when: