Tekton pipelines running with latest version of the operator are unable to run privileged jobs

Some tasks in the pipeline (particularly the build task that uses `buildah`) require privileged access to run. Previously, the tekton `pipeline` service account was given privileged access by default but with the latest version of the toolkit it appears that is no longer the case.

Pipelines fail with the following:

```
failed to create task run pod "test-typescript1-82plg5-build-b6sfx": pods "test-typescript1-82plg5-build-b6sfx-pod-bg9ps" is forbidden: unable to validate against any security context constraint: [spec.containers[1].securityContext.privileged: Invalid value: true: Privileged containers are not allowed spec.containers[1].securityContext.privileged: Invalid value: true: Privileged containers are not allowed spec.containers[1].securityContext.privileged: Invalid value: true: Privileged containers are not allowed]. Maybe missing or invalid Task edcig-dev/ibm-build-tag-push-v2-6-13
```