Add ability to specify Tag_Regex

**Is your feature request related to a problem?**
It would be nice to be able to specify a custom `Tag_Regex` for the `tail` input of the `aws-for-fluent-bit` helm chart.

**Is your feature request related to a specific Helm chart, if yes mention name of the chart?**
This is for the `aws-for-fluent-bit` chart.

**Describe the solution you'd like**
Add a variable to be able to specify the `Tag_Regex` param of the `fluent-bit` `tail` plugin: https://github.com/aws/eks-charts/blob/master/stable/aws-for-fluent-bit/templates/configmap.yaml

```
[INPUT]
Name tail
Tag {{ .Values.input.tag }}
---> Tag_Regex {{ .Values.input.tagRegex }}
Path {{ .Values.input.path }}
DB {{ .Values.input.db }}
Parser {{ .Values.input.parser }}
Docker_Mode {{ .Values.input.dockerMode }}
Mem_Buf_Limit {{ .Values.input.memBufLimit }}
Skip_Long_Lines {{ .Values.input.skipLongLines }}
Refresh_Interval {{ .Values.input.refreshInterval }}
```

Start with stable/aws-for-fluent-bit/templates/configmap.yaml and the chart's existing input values for the tail plugin. Add the configurable Tag_Regex value and verify that the rendered ConfigMap includes it for the aws-for-fluent-bit chart.

Written by the indexing model from the issue text.