fix CI release upload: switch to woodpecker/plugin-s3 (#428)

- this fixes the CI release upload issues, as the docker image for this is freshly built (unlike the mostly unmaintained "official" drone plugins), thus containing current CA certs needed for letsencrypt since 2021-09-31.
- woodpecker is a drone-ci fork maintained partially by @6543. it's API compatible with current drone plugins afaik

Co-authored-by: Norwin <git@nroo.de>
Reviewed-on: https://gitea.com/gitea/tea/pulls/428
Reviewed-by: Alexey 〒erentyev <axifive@noreply.gitea.io>
Reviewed-by: 6543 <6543@obermui.de>
Co-authored-by: Norwin <noerw@noreply.gitea.io>
Co-committed-by: Norwin <noerw@noreply.gitea.io>

.drone.yml

@@ -96,7 +96,7 @@ steps:
 
 - name: tag-release
   pull: always
-  image: plugins/s3:1
+  image: woodpeckerci/plugin-s3:latest
   settings:
     acl: public-read
     bucket: gitea-artifacts
@@ -116,7 +116,7 @@ steps:
 
 - name: release-branch-release
   pull: always
-  image: plugins/s3:1
+  image: woodpeckerci/plugin-s3:latest
   settings:
     acl: public-read
     bucket: gitea-artifacts
@@ -138,7 +138,7 @@ steps:
 
 - name: release
   pull: always
-  image: plugins/s3:1
+  image: woodpeckerci/plugin-s3:latest
   settings:
     acl: public-read
     bucket: gitea-artifacts