chore(deps): update nginx docker digest to 6af79ae (#141)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

.github/workflows/main.yml

@@ -111,7 +111,7 @@ jobs:
     # start nginx as service to test validation via http-challenge local path
     services:
       nginx:
-        image: nginx@sha256:67682bda769fae1ccf5183192b8daf37b64cae99c6c3302650f6f8bf5f0f95df
+        image: nginx@sha256:6af79ae5de407283dcea8b00d5c37ace95441fd58a8b1d2aa1ed93f5511bb18c
         volumes:
           - /tmp:/usr/share/nginx/html
         ports: