Introduce a git-clone task.

The official git-clone task her permission issues when cloning a private repo, so I'm introducing my own.

task/git-clone/0.1/git-clone.yaml

@@ -0,0 +1,60 @@
+apiVersion: tekton.dev/v1
+kind: Task
+metadata:
+  name: git-clone
+  labels:
+    app.kubernetes.io/version: "0.1"
+  annotations:
+    tekton.dev/categories: SCM
+    tekton.dev/pipelines.minVersion: "1.12.1"
+    tekton.dev/tags: scm
+    tekton.dev/displayName: "Clone a git repository."
+    tekton.dev/platforms: "linux/amd64"
+spec:
+  description: >-
+    This task will clone a git repository.
+  workspaces:
+    - name: output
+      mountPath: /output
+      readOnly: false
+  params:
+    - name: url
+      type: string
+      description: The repository url to clone.
+    - name: revision
+      type: string
+      description: The revision to clone.
+    - name: IMAGE
+      type: string
+      description: Docker image to use for performing the clone.
+      default: "alpine/git:v2.54.0"
+  results:
+    - name: commit
+      type: string
+      description: The commit hash that was cloned.
+    - name: url
+      type: string
+      description: The URL to the git repo.
+    - name: committer-date
+      type: string
+      description: The time of the git commit in unix timestamp format.
+  steps:
+    - name: fetch-repository-step
+      image: $(params.IMAGE)
+      workingDir: "$(workspaces.output.path)"
+      script: |
+        #!/usr/bin/env sh
+        set -euo pipefail
+        export GIT_SSH_COMMAND="ssh -o StrictHostKeyChecking=accept-new"
+        git init --initial-branch=main
+        git remote add origin $(params.url)
+        git fetch -v origin $(params.revision)
+        git checkout FETCH_HEAD
+
+        git rev-parse HEAD > $(results.commit.path)
+        echo "$(params.url)" > $(results.url.path)
+        echo -n "$(git log -1 --pretty=%ct)" > $(results.committer-date.path)
+      # securityContext:
+      #   runAsNonRoot: true
+      #   runAsUser: 1000
+      #   runAsGroup: 1000