Update tekton configuration and add a new dockerfile for downstream build

.konflux/Containerfile.plugin

@@ -0,0 +1,27 @@
+# Build Stage
+FROM  brew.registry.redhat.io/rh-osbs/openshift-golang-builder:rhel_8_golang_1.22 AS builder
+WORKDIR /go/src
+COPY . /go/src
+RUN GIT_COMMIT=$(git rev-parse HEAD) && \
+  CGO_ENABLED=0 GOOS=linux go build -a -mod=readonly \
+  -ldflags "-X github.com/redhat-developer/gitops-backend/pkg/health.GitRevision=${GIT_COMMIT}" ./cmd/backend-http
+
+# Final Stage
+FROM registry.access.redhat.com/ubi8/ubi-minimal
+WORKDIR /
+COPY --from=builder /go/src/backend-http .
+EXPOSE 8080
+ENTRYPOINT ["./backend-http"]
+
+LABEL \
+    name="openshift-gitops-1/gitops-rhel8" \
+    License="Apache 2.0" \
+    com.redhat.component="openshift-gitops-container" \
+    com.redhat.delivery.appregistry="false" \
+    upstream-vcs-type="git" \
+    summary="Red Hat OpenShift GitOps Backend Service" \
+    io.openshift.expose-services="" \
+    io.openshift.tags="openshift,gitops" \
+    io.k8s.display-name="Red Hat OpenShift GitOps Backend Service" \
+    maintainer="William Tam <[email protected]>" \
+    description="Red Hat OpenShift GitOps Backend Service"

.tekton/gitops-backend-pull-request.yaml

@@ -26,8 +26,15 @@ spec:
     value: quay.io/redhat-user-workloads/rh-openshift-gitops-tenant/openshift-gitops-operator/gitops-backend:on-pr-{{revision}}
   - name: image-expires-after
     value: 5d
+  - name: build-platforms
+    value:
+    - linux/x86_64
   - name: dockerfile
-    value: Dockerfile
+    value: .konflux/Containerfile.plugin
+  - name: hermetic
+    value: "true"
+  - name: prefetch-input
+    value: '{"type": "gomod", "path": "."}'
   pipelineSpec:
     description: |
       This pipeline is ideal for building multi-arch container images from a Containerfile while maintaining trust after pipeline customization.

.tekton/gitops-backend-push.yaml

@@ -23,8 +23,18 @@ spec:
     value: '{{revision}}'
   - name: output-image
     value: quay.io/redhat-user-workloads/rh-openshift-gitops-tenant/openshift-gitops-operator/gitops-backend:{{revision}}
+  - name: build-platforms
+    value:
+    - linux/x86_64
+    - linux/arm64
+    - linux/ppc64le
+    - linux/s390x
   - name: dockerfile
-    value: Dockerfile
+    value: .konflux/Containerfile.plugin
+  - name: hermetic
+    value: "true"
+  - name: prefetch-input
+    value: '{"type": "gomod", "path": "."}'  
   pipelineSpec:
     description: |
       This pipeline is ideal for building multi-arch container images from a Containerfile while maintaining trust after pipeline customization.

go.mod

@@ -2,6 +2,8 @@ module github.com/redhat-developer/gitops-backend
 
 go 1.22
 
+toolchain go1.22.5
+
 require (
 	github.com/argoproj/argo-cd v0.8.1-0.20210326223336-719d6a9c252e
 	github.com/go-git/go-git/v5 v5.1.0