[docs] SSL for Postgres

Updated the reference docs for offline/online stores to describe the SSL
options available

Signed-off-by: Neil Borle <nborle@atb.com>

docs/reference/offline-stores/postgres.md

@@ -13,6 +13,8 @@ The PostgreSQL offline store is an offline store that provides support for readi
      * `to_df` to retrieve the pandas dataframe.
      * `to_arrow` to retrieve the dataframe as a PyArrow table.
 
+* sslmode, sslkey_path, sslcert_path, and sslrootcert_path are optional
+
 ## Example
 
 {% code title="feature_store.yaml" %}
@@ -28,6 +30,10 @@ offline_store:
   db_schema: DB_SCHEMA
   user: DB_USERNAME
   password: DB_PASSWORD
+  sslmode: verify-ca
+  sslkey_path: /path/to/client-key.pem
+  sslcert_path: /path/to/client-cert.pem
+  sslrootcert_path: /path/to/server-ca.pem
 online_store:
     path: data/online_store.db
 ```

docs/reference/online-stores/postgres.md

@@ -6,6 +6,8 @@ The PostgreSQL online store provides support for materializing feature values in
 
 * Only the latest feature values are persisted
 
+* sslmode, sslkey_path, sslcert_path, and sslrootcert_path are optional
+
 ## Example
 
 {% code title="feature_store.yaml" %}
@@ -21,6 +23,10 @@ online_store:
     db_schema: DB_SCHEMA
     user: DB_USERNAME
     password: DB_PASSWORD
+    sslmode: verify-ca
+    sslkey_path: /path/to/client-key.pem
+    sslcert_path: /path/to/client-cert.pem
+    sslrootcert_path: /path/to/server-ca.pem
 ```
 {% endcode %}