enable Konflux cache proxy for builds

Enable the cache proxy in the Tekton pipeline definitions to improve
build performance by caching dependencies.

Ref: EC-1614
Signed-off-by: Rob Nester <rnester@redhat.com>

Author: robnester-rh

.tekton/cli-main-pull-request.yaml

@@ -40,6 +40,8 @@ spec:
     value: main-pre-merge-build-args.conf
   - name: hermetic
     value: "true"
+  - name: enable-cache-proxy
+    value: "true"
   pipelineSpec:
     description: |
       This pipeline is ideal for building container images from a Containerfile while maintaining trust after pipeline customization.

.tekton/cli-main-push.yaml

@@ -39,6 +39,8 @@ spec:
     value: main-build-args.conf
   - name: hermetic
     value: "true"
+  - name: enable-cache-proxy
+    value: "true"
   pipelineSpec:
     description: |
       This pipeline is ideal for building container images from a Containerfile while maintaining trust after pipeline customization.