ci: switch to drone-matrix plugin

.drone.yml

@@ -172,7 +172,7 @@ steps:
         - success
 
   - name: matrix
-  image: plugins/matrix
+    image: thegeeklab/drone-matrix
     settings:
       homeserver:
         from_secret: matrix_homeserver
@@ -180,7 +180,7 @@ steps:
         from_secret: matrix_password
       roomid:
         from_secret: matrix_roomid
-    template: "Status: **{{ build.status }}**<br/> Build: [{{ repo.Owner }}/{{ repo.Name }}]({{ build.link }}) ({{ build.branch }}) by {{ build.author }}<br/> Message: {{ build.message }}"
+      template: "Status: **{{ build.Status }}**<br/> Build: [{{ repo.Owner }}/{{ repo.Name }}]({{ build.Link }}) ({{ build.Branch }}) by {{ commit.Author }}<br/> Message: {{ commit.Message }}"
       username:
         from_secret: matrix_username
     when:
@@ -201,6 +201,6 @@ depends_on:
 
 ---
 kind: signature
-hmac: f0a79ff218867538b206db31be99e8dc07be3e50b1bb56e3e047a272816a33bf
+hmac: e30e31badb173a700dea1981548fad4470791bf6f3b284fe589d4864cad42e0d
 
 ...