CI: Update license & gitignore by cron (#14419)

do generate-license & generate-gitignore by cron

close #12684

Signed-off-by: a101211279 <1012112796@qq.com>

.drone.yml

@@ -433,6 +433,45 @@ steps:
       CROWDIN_KEY:
         from_secret: crowdin_key
 
+---
+kind: pipeline
+name: update_gitignore_and_licenses
+
+platform:
+  os: linux
+  arch: amd64
+
+workspace:
+  base: /go
+  path: src/code.gitea.io/gitea
+
+trigger:
+  branch:
+    - master
+  event:
+    - cron
+  cron:
+    - update_gitignore_and_licenses
+
+steps:
+  - name: download
+    image: golang:1.15
+    commands:
+      - timeout -s ABRT 40m make generate-license generate-gitignore
+
+  - name: push
+    pull: always
+    image: appleboy/drone-git-push
+    settings:
+      author_email: "teabot@gitea.io"
+      author_name: GiteaBot
+      commit: true
+      commit_message: "[skip ci] Updated licenses and gitignores "
+      remote: "git@github.com:go-gitea/gitea.git"
+    environment:
+      GIT_PUSH_SSH_KEY:
+        from_secret: git_push_ssh_key
+
 ---
 kind: pipeline
 name: release-latest