Add support for matrix parameters

[nielspardon]

Is your feature request related to a problem? Please describe.
Running tekton-lint against a pipeline using matrix parameters it does not seem to detect the matrix parameters and raises an error about missing parameters.

Describe the solution you'd like
It would be great if tekton-lint could detect matrix parameter definitions.

Describe alternatives you've considered
n/a

Additional context
https://tekton.dev/docs/pipelines/matrix/