nginx: add debian 11.3 support (#180)

Co-authored-by: Siim Kallas <[email protected]>

Author: Pondidum

.github/workflows/nginx.yml

@@ -18,7 +18,7 @@ jobs:
     runs-on: ubuntu-20.04
     strategy:
       matrix:
-        os: [ubuntu-20.04, ubuntu-18.04, debian-10.11]
+        os: [ubuntu-20.04, ubuntu-18.04, debian-10.11, debian-11.3]
         nginx-rel: [mainline, stable]
     steps:
       - name: checkout otel nginx