Fix charts.version for OCI chart rendering

[joryirving]

This is a prerequisite for #254

failed to create resource: Secret "minecraft-<name>-rcon" is invalid: [metadata.labels: Invalid value: "minecraft-4.25.0+efa491f67fbd": a valid label must be an empty string or consist of alphanumeric characters, '-', '_' or '.', and must start and end with an alphanumeric character (e.g. 'MyValue',  or 'my_value',  or '12345', regex used for validation is '(([A-Za-z0-9][-A-Za-z0-9_.]*)?[A-Za-z0-9])?'), metadata.labels: Invalid value: "4.25.0+efa491f67fbd": a valid label must be an empty string or consist of alphanumeric characters, '-', '_' or '.', and must start and end with an alphanumeric character (e.g. 'MyValue',  or 'my_value',  or '12345', regex used for validation is '(([A-Za-z0-9][-A-Za-z0-9_.]*)?[A-Za-z0-9])?')]

[itzg]

Thanks, that looks much better with the template function.