csi.storage.k8s.io/fstype is case sensitive

[jsafrane]

Is this a bug fix or adding new feature?
bug

What is this PR about? / Why do we need it?
The external-provisioner does not treat csi.storage.k8s.io/fstype as case-insensitive. Update the documentation accordingly.

What testing is done?
None :-)

[coveralls]

Pull Request Test Coverage Report for Build 1746

• 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 81.789%

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Totals
Change from base Build 1745:	0.0%
Covered Lines:	1756
Relevant Lines:	2147

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💛 - Coveralls

[wongma7]

w8 isn't this a bug in external provisioner too then?

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: jsafrane, wongma7

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