dependabot(docker): bump caddy from 2.8.4-alpine to 2.9.1-alpine

Bumps caddy from 2.8.4-alpine to 2.9.1-alpine.

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

Signed-off-by: dependabot[bot] <support@github.com>

Dockerfile

@@ -15,7 +15,7 @@ RUN npm i && \
 # Docker final environment #
 ############################
 
-FROM caddy:2.8.4-alpine
+FROM caddy:2.9.1-alpine
 
 LABEL maintainer="OpenChia <contact@openchia.io>" \
       description="OpenChia Angular Website" \