Add code coverage CI

.drone.yml

@@ -13,6 +13,16 @@ steps:
     commands:
       - apk add bats curl
       - bats test.bats
+
+  - name: collect code coverage
+    image: robertstettner/drone-codecov
+    commands:
+      - apk add kcov
+      - mkdir -p coverage && kcov coverage abra
+      - /bin/drone-codecov -s coverage
+    secrets:
+      - codecov_token
+
 trigger:
   branch:
     - main