fix(ical-proxy): roll out main-73b5d97 (WriteTimeout above fetch timeout)

Bump the pinned ical-proxy image from main-4783abe to main-73b5d97.
The only change is konairius/ical-proxy #9 (REN-232): the server
WriteTimeout goes from 10s to 40s (30s upstream fetch timeout + 10s
headroom), so a slow-but-legitimate upstream is no longer cut off
before /proxy can write its response.

Refs: REN-239, REN-232

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

kubernetes/apps/ical-proxy/deployment.yaml

@@ -43,12 +43,15 @@ spec:
           # resolving to private/loopback/link-local addresses are refused;
           # public redirects are still followed, up to 5) and a cap of 20
           # concurrent /proxy upstream fetches (over the cap: 429 +
-          # Retry-After). The summary_match/summary_replace parameters this
-          # deployment needs are unchanged.
+          # Retry-After). main-73b5d97 then raises the server WriteTimeout
+          # from 10s to 40s (the 30s upstream fetch timeout + 10s headroom),
+          # so a slow-but-legitimate upstream is no longer cut off before
+          # /proxy can answer. The summary_match/summary_replace parameters
+          # this deployment needs are unchanged.
           #
           # Bumping this is a manual, reviewed edit. The tag format is
           # main-<short-sha>, the first 7 characters of the main commit.
-          image: gitea.renner.uno/konairius/ical-proxy:main-4783abe
+          image: gitea.renner.uno/konairius/ical-proxy:main-73b5d97
           ports:
             - containerPort: 8080
               name: http