Update CEL GO to v0.9.0 and CEL Spec to v0.6.0

[khrm]

Update CEL GO to v0.9.0 for fixing bugs and improving cel performance.
https://github.com/google/cel-go/releases/tag/v0.9.0
https://github.com/google/cel-go/releases/tag/v0.8.0

Changes

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[khrm]

/test pull-tekton-triggers-integration-tests

[tekton-robot]

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This pull-request has been approved by: dibyom

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[dibyom]

Any breaking changes in CEL to be aware of? Also, can we call this out in the release notes section?

[TristonianJones]

There have been some substantial improvements and changes to CEL even since 0.9.0. I was about to publish the following pull request and saw this one:
main...TristonianJones:cel-upgrade

@dibyom The biggest change in v0.10.* and beyond is support for heterogeneous equality which should improve
the ease of use for working with JSON data as it will finally support the following expressions without an error:
json.field != null. Additionally, there have been some pretty substantial improvements to the CEL environment
bootstrapping and evaluation paths when working with lists.

[dibyom]

/lgtm