Upgrade Gitea dependencies (#141)

- postgresql 9.7.2 to 10.3.17
- mariadb 8.0.0 to 9.3.6
- memcached 4.2.20 to 5.9.0

Tested on my clusters.

Co-authored-by: Lucas Hahn <lucas.hahn@novum-rgi.de>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>
Reviewed-on: https://gitea.com/gitea/helm-chart/pulls/141
Reviewed-by: Andrew Thornton <art27@cantab.net>
Reviewed-by: techknowlogick <techknowlogick@gitea.io>
Co-authored-by: luhahn <luhahn@noreply.gitea.io>
Co-committed-by: luhahn <luhahn@noreply.gitea.io>

Chart.yaml

@@ -30,7 +30,7 @@ maintainers:
 dependencies:
 - name: memcached
   repository: https://charts.bitnami.com/bitnami
-  version: 4.2.20
+  version: 5.9.0
   condition: gitea.cache.builtIn.enabled
 - name: mysql
   repository: https://charts.bitnami.com/bitnami
@@ -38,9 +38,9 @@ dependencies:
   condition: gitea.database.builtIn.mysql.enabled
 - name: postgresql
   repository: https://charts.bitnami.com/bitnami
-  version: 9.7.2
+  version: 10.3.17
   condition: gitea.database.builtIn.postgresql.enabled
 - name: mariadb
   repository: https://charts.bitnami.com/bitnami
-  version: 8.0.0
+  version: 9.3.6
   condition: gitea.database.builtIn.mariadb.enabled