Upgrade mariadb Helm chart to 8.0.0 (#48)

Upgrade mariadb Helm chart to 8.0.0

The names of the values changed in the new Helm chart, see [1]. Thus the
Helm chart ships breaking changes and therefore bump the major version
of this Chart.yaml (not sure if you use semver?)

Furthermore, there is a bug [2] where not setting the root password
results in the mariadb entering a CrashLoopBackOff when re-installing
it. Thus set it (as done in the mysql values already).

[1] 1206942b69
[2] https://github.com/bitnami/charts/issues/3884

Co-authored-by: Andre Schröder <andre.schroedr@gmail.com>
Reviewed-on: https://gitea.com/gitea/helm-chart/pulls/48
Reviewed-by: Andrew Thornton <art27@cantab.net>
Reviewed-by: luhahn <luhahn@noreply.gitea.io>
Co-Authored-By: schra <schra@noreply.gitea.io>
Co-Committed-By: schra <schra@noreply.gitea.io>

values.yaml

@@ -140,12 +140,13 @@ mysql:
     size: 10Gi
 
 mariadb:
-  db:
-    name: gitea
-    user: gitea
+  auth:
+    database: gitea
+    username: gitea
     password: gitea
-  service:
-    port: 3306
-  master:
+    rootPassword: gitea
+  primary:
+    service:
+      port: 3306
     persistence:
       size: 10Gi