docs: add woodpecker ci (#3516)

This PR adds [woodpecker](https://woodpecker-ci.org) to the CI docs.

Signed-off-by: jolheiser <john.olheiser@gmail.com>

www/docs/ci/woodpecker.md

@@ -0,0 +1,24 @@
+# Woodpecker
+
+By default, woodpecker only fetches tags on `tag` events. If you are not using a tag event, you will need to override the git plugin like so:
+
+```yaml
+clone:
+  git:
+    image: woodpeckerci/plugin-git
+    settings:
+      tags: true
+```
+
+Here is how to set up a basic release pipeline with [Woodpecker](https://woodpecker-ci.org) and [Gitea](https://gitea.io).
+
+```yaml
+pipeline:
+  release:
+    image: goreleaser/goreleaser
+    commands:
+      - goreleaser release
+    secrets: [ gitea_token ]
+    when:
+      event: tag
+```

www/mkdocs.yml

@@ -70,6 +70,7 @@ nav:
   - ci/jenkins.md
   - ci/semaphore.md
   - ci/travis.md
+  - ci/woodpecker.md
 - Customization:
   - About: customization/index.md
   - Basics: