Update GH pages to point to main branch

[kkourtchikov]

Describe the bug
It looks like the GH pages setup for couchdb-helm is still pointing to the master branch, while the latest version of the chart is being deployed to the main branch. In order to complete the transition from master->main, .asf.yaml should be updated and/or the branch in this repo's [Settings -> Pages -> Source] option should be changed to point to the main branch. It may also be helpful to delete the master branch to reduce future confusion.

Version of Helm and Kubernetes:
Helm 3.7.2

What happened:
Followed README for setting up couchdb Helm repo, and found couchdb-helm v3.3.4 and couchdb 3.1.0 installed per master's index.yaml.

What you expected to happen:
Expected couchdb-helm 3.4.0 and couchdb 3.2.0 to be installed per main's index.yaml.

How to reproduce it (as minimally and precisely as possible):
Follow installation instructions in couchdb-helm README

Anything else we need to know: