Added a message to create a subscription after running the pipeline (#341)

[avas27JTG]

Summary

Added a message to create a subscription after running the pipeline (#341)

Screenshot

• In case of no existing subscription for the given project

• In case of an existing subscription for the given project but a different feature than the pipeline

Ticket Link

Fixes #341

[codecov[bot]]

Codecov Report

Attention: 22 lines in your changes are missing coverage. Please review.

Comparison is base (ee780c1) 33.40% compared to head (ef80e1d) 33.21%.

Files	Patch %	Lines
server/command.go	0.00%	22 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #445 +/- ## ========================================== - Coverage 33.40% 33.21% -0.19% ========================================== Files 22 22 Lines 3979 4001 +22 ========================================== Hits 1329 1329 - Misses 2519 2541 +22 Partials 131 131 ```

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[mickmister]

I think this is already implemented here right? https://github.com/mattermost/mattermost-plugin-gitlab/pull/433

[raghavaggarwal2308]

@mickmister I think there was some confusion here. We can close this PR and continue with #433 as that is already in the review process.