doc: update new chart versions

[andyzhangx]

What type of PR is this?
/kind documentation

What this PR does / why we need it:
doc: update new chart versions

git checkout -b add-chart-versions

sed -i 's/v4.12.0/v4.12.1/g' README.md
sed -i 's/v4.12.0/v4.12.1/g' docs/install-nfs-csi-driver.md
sed -i 's/4.12.0/4.12.1/g' charts/README.md

git diff

helm repo index charts --url=https://raw.githubusercontent.com/kubernetes-csi/csi-driver-nfs/master/charts
git add charts deploy docs
$git_commit
git push origin add-chart-versions

Which issue(s) this PR fixes:

Fixes #

Requirements:

• uses conventional commit messages
• includes documentation
• adds unit tests
• tested upgrade from previous version

Special notes for your reviewer:

Release note:

none

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: andyzhangx

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [andyzhangx]

Approvers can indicate their approval by writing /approve in a comment
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[coveralls]

Pull Request Test Coverage Report for Build 18489086528

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 78.693%

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Totals
Change from base Build 18421542992:	0.0%
Covered Lines:	1108
Relevant Lines:	1408

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💛 - Coveralls