Set Redis verification mode for TLS connections.

If the app is making a TLS connection to Redis, the new config setting
REDIS_SSLMODE determines whether CA verification should be performed.
Acceptable values are Python `None` or strings "none", "optional", and
"required".

.secrets.baseline

@@ -3,7 +3,7 @@
     "files": "^.secrets.baseline$|^.*pgsslrootcert.yml$",
     "lines": null
   },
-  "generated_at": "2020-01-27T19:24:43Z",
+  "generated_at": "2020-02-10T21:40:38Z",
   "plugins_used": [
     {
       "base64_limit": 4.5,
@@ -82,7 +82,7 @@
         "hashed_secret": "afc848c316af1a89d49826c5ae9d00ed769415f3",
         "is_secret": false,
         "is_verified": false,
-        "line_number": 32,
+        "line_number": 33,
         "type": "Secret Keyword"
       }
     ],