travis: upgraded OpenSSL to 1.1.1s.

.travis.yml

@@ -111,7 +111,7 @@ env:
     - OPENRESTY_PREFIX=/opt/openresty
   jobs:
     - OPENSSL_VER=1.1.0l OPENSSL_PATCH_VER=1.1.0d
-    - OPENSSL_VER=1.1.1p OPENSSL_PATCH_VER=1.1.1f
+    - OPENSSL_VER=1.1.1s OPENSSL_PATCH_VER=1.1.1f
 
 jobs:
     include:
@@ -120,7 +120,7 @@ jobs:
         - <<: *linux-s390x
           env: OPENSSL_VER=1.1.1l OPENSSL_PATCH_VER=1.1.1f
         - <<: *linux-ppc64le
-          env: OPENSSL_VER=1.1.1p OPENSSL_PATCH_VER=1.1.1f
+          env: OPENSSL_VER=1.1.1s OPENSSL_PATCH_VER=1.1.1f
 
 install:
   - sudo cpanm --notest Test::Nginx IPC::Run3 > build.log 2>&1 || (cat build.log && exit 1)