Skip gitlab jobs when some files are modified

When we modified only a file like ReleaseNotes.md we want to avoid to trigger some jobs to accelerate the development process.

Files:

**/*.md
**/*.txt
sonar-project.properties
**/README
COPYING

Merge Request Pipelines

Merge request pipelines:

Do not run by default. The jobs in the CI/CD configuration file must be configured to run in merge request pipelines.
If configured, merge request pipelines run when you:
    Create a new merge request from a source branch with one or more commits.
    Push a new commit to the source branch for a merge request.
    Select Run pipeline from the Pipelines tab in a merge request. This option is only available when merge request pipelines are configured for the pipeline and the source branch has at least one commit.
Have access to more predefined variables.
Do not have access to protected variables or protected runners.

https://docs.gitlab.com/ee/ci/pipelines/merge_request_pipelines.html