Bump openresty/openresty in /compas/reverse-proxy

Bumps openresty/openresty from 1.21.4.1-6-alpine-fat to 1.21.4.3-2-alpine-fat.

---
updated-dependencies:
- dependency-name: openresty/openresty
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

compas/reverse-proxy/Dockerfile

@@ -5,7 +5,7 @@
 # We want to go back to below image, but it seems to be broken.
 # For now use fixed version which still works.
 #FROM openresty/openresty:alpine-fat
-FROM openresty/openresty:1.21.4.1-6-alpine-fat
+FROM openresty/openresty:1.21.4.3-2-alpine-fat
 
 ARG COMPAS_HOSTNAME
 ARG CONFIGURATION_LOCATION