Bump caddy from 2.8.4 to 2.9.1

Bumps caddy from 2.8.4 to 2.9.1.

---
updated-dependencies:
- dependency-name: caddy
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

Dockerfile

@@ -1,8 +1,8 @@
-FROM caddy:2.8.4-builder AS builder
+FROM caddy:2.9.1-builder AS builder
 
 RUN xcaddy build \
     --with github.com/caddy-dns/cloudflare
 
-FROM caddy:2.8.4
+FROM caddy:2.9.1
 
 COPY --from=builder /usr/bin/caddy /usr/bin/caddy