travis-ci: upgraded openssl to 1.1.1l.

Author: xiaocang

.travis.yml

@@ -36,7 +36,7 @@ env:
     - TEST_NGINX_SLEEP=0.006
   matrix:
     - NGINX_VERSION=1.19.9 OPENSSL_VER=1.1.0l
-    - NGINX_VERSION=1.19.9 OPENSSL_VER=1.1.1k
+    - NGINX_VERSION=1.19.9 OPENSSL_VER=1.1.1l
 
 services:
  - memcache