[bitnami/contour]: Fix invalid extraVolumeMounts

[uubk]

Description of the change

The default backend's deployment.yaml currently contains the following code:

          {{- if .Values.defaultBackend.extraVolumeMounts }}
          volumeMounts: {{- include "common.tplvalues.render" ( dict "value" .Values.contour.extraVolumeMounts "context" $ ) | nindent 12 }}
          {{- end }}

Note that the if condition uses the correct variable (defaultBackend.extraVolumeMounts) whereas the render call uses the incorrect one (contour.extraVolumeMounts). This looks like a simple copy and paste mistake.

Benefits

The default backends' volumes get rendered correctly.

Checklist

• Chart version bumped in Chart.yaml according to semver. This is not necessary when the changes only affect README.md files.
• Title of the pull request follows this pattern [bitnami/<name_of_the_chart>] Descriptive title
• All commits signed off and in agreement of Developer Certificate of Origin (DCO)