feat: Automatic link for gitlab merge requests

[barryib]

What does this do / why do we need it?

This will add link for merge requests for gitlab style. See #159 for more details.

How this PR fixes the problem?

It follow gitlab merge request links standards.

Check lists

• Test passed
• Coding style (indentation, etc)

Which issue(s) does this PR fix?

fixes #159

[coveralls]

Pull Request Test Coverage Report for Build 1011881492

• 4 of 4 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.04%) to 76.808%

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Totals
Change from base Build 1000413462:	0.04%
Covered Lines:	1848
Relevant Lines:	2406

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💛 - Coveralls

[barryib]

Adding @khos2ow @mavogel as reviewers

[dbluxo]

Is there anything special that needs to be activated? I have selected the gitlab style, but the merge requests do not appear as links, but only as follows:

<a name="2021.09.22"></a>
## [2021.09.22] - 2021-09-22
### Merge Requests
- Merge branch 'renovate/aws-ebs-csi-driver-2.x' into 'main'
- Merge branch 'renovate/aws-ebs-csi-driver-2.x' into 'main'
- Merge branch 'renovate/aws-ebs-csi-driver-2.x' into 'main'
- Merge branch 'renovate/cluster-autoscaler-9.x' into 'main'
- Merge branch 'renovate/cluster-autoscaler-9.x' into 'main'
- Merge branch 'renovate/kubernetes-dashboard-5.x' into 'main'
- Merge branch 'renovate/kubernetes-dashboard-4.x' into 'main'
- Merge branch '38-add-correct-tags-to-ebs-pvcs' into 'main'