feat: Restrict the CI to Go files

.woodpecker.yml

@@ -1,11 +1,20 @@
+x-anchors:
+  golang_filter: &golang_filter
+    - path:
+      include: [ "**/*.go" ]
+
 steps:
   build:
     image: "golang:1.21.5-alpine"
     commands:
       - go build ./cmd/rio
       - go test $(go list ./... | grep -v /vendor/)
+    when:
+      - <<: *golang_filter
   lint:
     image: "golang:1.21.5-alpine"
     commands:
       - go fmt $(go list ./... | grep -v /vendor/)
-      - go vet $(go list ./... | grep -v /vendor/)
+      - go vet $(go list ./... | grep -v /vendor/)
+    when:
+      - <<: *golang_filter

README.md

@@ -72,6 +72,18 @@ _acme-challenge.cooldomain.rio. 3600    IN  CNAME   cooldomain.rio.pages.example
 This additionally requires your repository to have a file named `CNAME` that contains
 the domain to use (`cooldomain.rio` in this case).
 
+### Alternate CNAME Domains
+
+If there is a situation where you want to use a CNAME redirect on a (sub-) domain,
+where having a CNAME is not feasible, you can configure an "alternate CNAME".
+This is a special TXT record that contains the "CNAME" you want to specify.
+
+```
+; Example for Bind
+cooldomain.rio.                 3600    IN  A       <IPv4 of rio>
+_rio-cname.cooldomain.rio.      3600    IN  TXT     "cname=user.pages.example.org"
+```
+
 ### Repository Redirects
 
 If you have multiple repositories with pages (and you use a CNAME), you can additionally