Update to Matomo 5.1.1

Why these changes are being introduced:
UXWS requested an upgrade from 5.1.0 to 5.1.1 for Matomo.

How this addresses that need:
* Update the Dockerfile to pull the 5.1.1 version of the Matomo
container
* Update the config.ini.php file to reflect the fact that we are using
Maria DB (not MySQL) for the database
* Update the config.ini.php file to fix the issue that the Matomo
System Check page did not recognize that the database had already
enabled the utf8mb4 character set.

Side effects of this change:
None.

Relevant ticket(s):
* https://mitlibraries.atlassian.net/browse/INFRA-471

Author: cabutlermit

Dockerfile

@@ -1,4 +1,4 @@
-FROM matomo:5.1.0
+FROM matomo:5.1.1
 
 # Add the EnvironmentVariables plugin
 COPY ./files/plugin-EnvironmentVariables-5.0.0/ /var/www/html/plugins/EnvironmentVariables

files/config.ini.php

@@ -1,6 +1,8 @@
 ; <?php exit; ?> DO NOT REMOVE THIS LINE
 ; file automatically generated or modified by Matomo; you can manually override the default values in global.ini.php by redefining them in this file.
 [database]
+schema = Mariadb
+charset = utf8mb4
 
 [General]
 proxy_client_headers[] = "HTTP_X_FORWARDED_FOR"