fix: variable substition

.drone.yml

@@ -8,7 +8,7 @@ trigger:
     - 2022-2023
 
 steps:
-  - name: Build Opytex {{ DRONE_BRANCH }}
+  - name: Build Opytex ${DRONE_BRANCH}
     image: python:3.8-alpine
     volumes:
       - name: pelican-output
@@ -17,7 +17,7 @@ steps:
       - apk add --no-cache git imagemagick-dev imagemagick
       - git submodule init
       - git submodule update
-      - git clone https://git.opytex.org/lafrite/{{ DRONE_BRANCH }}.git content
+      - git clone https://git.opytex.org/lafrite/${DRONE_BRANCH}.git content
       - pip install --no-cache-dir -r requirements.txt
       - apk add --no-cache git imagemagick-dev imagemagick
       - pip install --no-cache-dir -r requirements.txt
@@ -38,7 +38,7 @@ steps:
       secret_key:
         from_secret: minio_secret_key
       source: /output
-      target: /enseignements/{{ DRONE_BRANCH }}
+      target: /enseignements/${DRONE_BRANCH}
       path_style: true
       delete: true