CI: use from_secret instead of deprecated secrets

.woodpecker.yaml

@@ -27,7 +27,9 @@ steps:
 
   deploy:
     image: alpine
-    secrets: [ deploy_key ]
+    environment:
+      DEPLOY_KEY:
+        from_secret: deploy_key
     commands:
       - apk add rsync openssh
       - mkdir ~/.ssh
@@ -44,7 +46,9 @@ steps:
 
   commit:
     image: alpine
-    secrets: [ ssh_key ]
+    environment:
+      SSH_KEY:
+        from_secret: ssh_key
     commands:
       - apk add git openssh
       # configure git