Use proper link to integration test guide

[gazayas]

Originating Project/Creator	Gabriel Zayas
Affected Component	None
Affected Architectures(s)	None
Related Issue(s)	None
Has Unit Tests (y/n)	n
Builds Without Errors (y/n)	y
Unit Tests Pass (y/n)	y
Documentation Included (y/n)	y

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Change Description

Fixes a link to the GDS integration test guide.

Rationale

I was thinking about tackling #1561, but I found that I couldn't access the link to the integration test guide, so I added the fix here.

If you have any pointers for #1561 by the way, I'd be glad to try it out since it has an "Easy First Issue" label.

[thomas-bc]

LGTM, thanks for fixing!