Clone the git repo instead of using ADD.

Using ADD breaks the caching.

.webhook_bridge/pipeline-foreign-document-test.yaml

@@ -103,7 +103,7 @@ spec:
             - name: url
               value: https://code.fizz.buzz/talexander/personal_tekton_catalog.git
             - name: revision
-              value: f909b6670474346e37a57a2d23131860b6a1a635
+              value: 1331a038089a458c4072caa4cbc0cd57f70e3388
             - name: pathInRepo
               value: task/buildah-rootless-daemonless/0.1/buildah-rootless-daemonless.yaml
         params:
@@ -143,6 +143,8 @@ spec:
             workspace: git-source
           - name: dockerconfig
             workspace: docker-credentials
+          - name: buildah-storage
+            workspace: buildah-storage
         runAfter:
           - fetch-repository
       - name: run-test
@@ -286,6 +288,7 @@ spec:
       - name: git-source
       - name: docker-credentials
       - name: cargo-cache
+      - name: buildah-storage
   workspaces:
     - name: git-source
       volumeClaimTemplate:
@@ -297,6 +300,16 @@ spec:
             requests:
               storage: 10Gi
       subPath: rust-source
+    - name: buildah-storage
+      volumeClaimTemplate:
+        spec:
+          storageClassName: "local-path"
+          accessModes:
+            - ReadWriteOnce
+          resources:
+            requests:
+              storage: 10Gi
+      subPath: buildah-storage
     - name: cargo-cache
       persistentVolumeClaim:
         claimName: organic-cargo-cache-test-foreign-document