Build/Test Tools: Expand and improve MariaDB test matrix.

The latest LTS version of MariaDB is 11.4, which is now included in the test matrix.

This changeset also expands the test matrix to include all LTS versions of MariaDB with > 1% of usage on WordPress sites in the wild as reported by the stats page on WordPress.org. Though a few of these are unsupported upstream, they are still supported in WordPress itself.

MariaDB 5.5 is also included in the new matrix. Because it was intended as a drop-in replacement to MySQL at the time, this also brings some MySQL 5.5 testing into the matrix. This has not been regularly tested against since specific database versions were included due to the lack of a working Docker container.

Props johnbillion, jorbin.
See #62221.

git-svn-id: https://develop.svn.wordpress.org/trunk@59587 602fd350-edb4-49c9-b593-d223f7449a82

.github/workflows/phpunit-tests.yml

@@ -118,7 +118,7 @@ jobs:
         os: [ ubuntu-latest ]
         php: [ '7.2', '7.3', '7.4', '8.0', '8.1', '8.2', '8.3', '8.4' ]
         db-type: [ 'mariadb' ]
-        db-version: [ '10.4', '10.6', '10.11', '11.2' ]
+        db-version: [ '5.5', '10.3', '10.4', '10.5', '10.6', '10.11', '11.4' ]
         multisite: [ false, true ]
         memcached: [ false ]
 
@@ -127,13 +127,13 @@ jobs:
         - os: ubuntu-latest
           php: '8.3'
           db-type: 'mariadb'
-          db-version: '11.2'
+          db-version: '11.4'
           multisite: false
           memcached: true
         - os: ubuntu-latest
           php: '8.3'
           db-type: 'mariadb'
-          db-version: '11.2'
+          db-version: '11.4'
           multisite: true
           memcached: true
     with: