chore(deps): update container image cthulhoo/ttrss-web-nginx to latest@a724a6f by renovate (#21123)

This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
| cthulhoo/ttrss-web-nginx | digest | `45a5e02` -> `a724a6f` |

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This PR has been generated by [Renovate
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<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiIzNy4zMTUuMCIsInVwZGF0ZWRJblZlciI6IjM3LjMxNS4wIiwidGFyZ2V0QnJhbmNoIjoibWFzdGVyIiwibGFiZWxzIjpbImF1dG9tZXJnZSIsInVwZGF0ZS9kb2NrZXIvZ2VuZXJhbC9ub24tbWFqb3IiXX0=-->

charts/stable/tt-rss/Chart.yaml

@@ -35,4 +35,4 @@ sources:
   - https://hub.docker.com/r/cthulhoo/ttrss-fpm-pgsql-static
   - https://hub.docker.com/r/cthulhoo/ttrss-web-nginx
 type: application
-version: 16.8.20
+version: 16.8.21

charts/stable/tt-rss/values.yaml

@@ -5,7 +5,7 @@ image:
 nginxImage:
   repository: cthulhoo/ttrss-web-nginx
   pullPolicy: IfNotPresent
-  tag: latest@sha256:45a5e02be1a9c41af5016884b6346d943a0018e79e0b29bc04e715547f648461
+  tag: latest@sha256:a724a6f94a829272b0bfbf358edd20ec133711fe138db2ad0078baaa7263a5bc
 updaterImage:
   repository: cthulhoo/ttrss-fpm-pgsql-static
   pullPolicy: IfNotPresent