fix: let's encrypt auto-revoked certificates

Let's Encrypt started mass-revoking certificates. For some reason, we
did not upgrade to the latest version of Caddy in the Maple upgrade, so
we are affected by this issue. Users should upgrade now.

See:
https://discuss.overhang.io/t/lets-encrypt-revoked-certificate-did-anyone-experienced-this/2391
https://discuss.overhang.io/t/ssl-error-in-the-browser/2390
https://community.letsencrypt.org/t/questions-about-renewing-before-tls-alpn-01-revocations/170449/21

CHANGELOG.md

@@ -4,6 +4,8 @@ Note: Breaking changes between versions are indicated by "💥".
 
 ## Unreleased
 
+- [Bugfix] Fix auto-renewal of certificates revoked by Let's Encrypt (see [discussion](https://community.letsencrypt.org/t/questions-about-renewing-before-tls-alpn-01-revocations/170449/21)). 
+
 ## v13.1.1 (2022-01-25)
 
 - [Bugfix] Fix authentication in development due to missing SameSite policy on session ID cookie.

tutor/templates/config/defaults.yml

@@ -11,7 +11,7 @@ DEV_PROJECT_NAME: "{{ TUTOR_APP }}_dev"
 DOCKER_REGISTRY: "docker.io/"
 DOCKER_IMAGE_OPENEDX: "{{ DOCKER_REGISTRY }}overhangio/openedx:{{ TUTOR_VERSION }}"
 DOCKER_IMAGE_OPENEDX_DEV: "openedx-dev"
-DOCKER_IMAGE_CADDY: "docker.io/caddy:2.3.0"
+DOCKER_IMAGE_CADDY: "docker.io/caddy:2.4.6"
 DOCKER_IMAGE_ELASTICSEARCH: "docker.io/elasticsearch:7.10.1"
 DOCKER_IMAGE_MONGODB: "docker.io/mongo:4.2.17"
 DOCKER_IMAGE_MYSQL: "docker.io/mysql:5.7.35"