refactor tag and build arg handling (removed matrix build)

.drone.yml

@@ -4,9 +4,20 @@ pipeline:
     image: plugins/docker
     repo: bunix42/ttrss
     build_args:
-      - TTRSS_GIT_TAG=${TTRSS_GIT_TAG}
+      - TTRSS_GIT_TAG=master
+      - FEEDLY_GIT_TAG=master
     tags:
-     - ${TTRSS_GIT_TAG}
+     - latest
+    secrets: [ docker_username, docker_password ]
+
+  docker:
+    image: plugins/docker
+    repo: bunix42/ttrss
+    build_args:
+      - TTRSS_GIT_TAG=19.2
+      - FEEDLY_GIT_TAG=2.2.0
+    tags:
+     - 19.2
     secrets: [ docker_username, docker_password ]
 
   slack:
@@ -14,8 +25,3 @@ pipeline:
     channel: drone
     username: drone
     secrets: [ slack_webhook ]
-
-matrix:
-  TTRSS_GIT_TAG:
-    - master
-    - 19.2