Not able to configure git resolver using SSH url of git instead of HTTPS url.

Resolution fails with below error

~~~
Error retrieving pipeline for pipelinerun default/git-pipeline-reference-demo1: resolver failed to get Pipeline : error requesting remote resource: error getting "Git" "default/git-abd0cfdbcc134dc44a2f2330d942d26d": clone error: error creating SSH agent: "SSH agent requested but SSH_AUTH_SOCK not-specified"

~~~

Documentation doesn't mentions any specific was to use SSH URL, so not sure if it's supported.

Below is resolver config.

~~~
git-resolver-config:
api-token-secret-key: github-auth-key
api-token-secret-name: github-auth-secret
api-token-secret-namespace: sendmail
default-org: tektoncd
default-revision: main
fetch-timeout: 1m
scm-type: github
 
~~~

Test PipelineRun

~~~

apiVersion: tekton.dev/v1
kind: PipelineRun
metadata:
  name: git-pipeline-reference-demo
spec:
  pipelineRef:
    resolver: git
    params:
    - name: url
      value: git@github.com:tektoncd/catalog.git
    - name: revision
      value: main
    - name: pathInRepo
      value: pipeline/buildpacks/0.1/buildpacks.yaml
  params:
  - name: name
    value: "testPipelineRun"
  - name: sample-pipeline-parameter
    value: test

~~~

I tried using Github personal token, SSH private key and application API key as value for api-token-secret-key.

Issue is always reproducible.