chore: add git workflow to delete old branches in pactflow

.github/workflows/delete_branch_in_pactflow.yml

@@ -0,0 +1,24 @@
+name: Delete application branch in Pactflow
+
+on:
+  delete:
+    branches:
+      - "*"
+
+jobs:
+  delete-branch-in-pactflow:
+    name: delete
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+      # Requires Ruby to encode the URL path correctly - could use any other scripting language here
+      - uses: ruby/setup-ruby@v1
+
+      - name: Delete branch ${GIT_BRANCH} for application ${PACTICIPANT} in Pactflow
+        run: script/ci/delete-branch-in-pactflow.sh
+        env:
+          GIT_BRANCH: ${{ github.event.ref }}
+          PACTICIPANT: "Pact Broker Client"
+          PACT_BROKER_TOKEN: ${{ secrets.PACT_BROKER_TOKEN_PACT_FOUNDATION }}
+          PACT_BROKER_BASE_URL=https://pact-foundation.pactflow.io

script/ci/delete-branch-in-pactflow.sh

@@ -0,0 +1,22 @@
+#!/bin/bash
+
+set -Eeuo pipefail
+
+echo "Deleting branch ${GIT_BRANCH} for ${PACTICIPANT} in Pactflow..."
+ENCODED_GIT_BRANCH=$(echo "$GIT_BRANCH" | ruby -e "require 'erb'; puts ERB::Util.url_encode(ARGF.read.chomp)")
+ENCODED_PACTICIPANT=$(echo "$PACTICIPANT" | ruby -e "require 'erb'; puts ERB::Util.url_encode(ARGF.read.chomp)")
+BRANCH_URL="${PACT_BROKER_BASE_URL}/pacticipants/${ENCODED_PACTICIPANT}/branches/${ENCODED_GIT_BRANCH}"
+
+output_file=$(mktemp)
+
+status=$(curl -v -X DELETE "${BRANCH_URL}" -H "Authorization: Bearer ${PACT_BROKER_TOKEN}" 2>&1 | tee "${output_file}" | awk '/^< HTTP/{print $3}')
+
+if [ "$status" = "404" ]; then
+  echo "Branch ${GIT_BRANCH} for ${PACTICIPANT} does not exist in Pactflow"
+elif [ $status -ge 400 ]; then
+  cat "${output_file}"
+  echo "Error deleting branch in Pactflow"
+  exit 1
+else
+  echo "Deleted branch ${GIT_BRANCH} for ${PACTICIPANT} in Pactflow"
+fi