Introduce reusable workflows into versions repositories (#60)

.github/workflows/validate-manifest.yml

@@ -0,0 +1,51 @@
+# This reusable workflow is used by actions/*-versions repositories
+# It is designed to validate the versions-manifest.json file
+# The 'SLACK_CHANNEL_URL' secret must be added to the repository containing the caller workflow 
+# in order to publish messages to Slack
+
+name: Validate manifest
+on:
+  workflow_call:
+    inputs:
+      tool-name:
+        description: 'Name of the tool for which manifest is validated'
+        required: true
+        type: string
+      image-url:
+        description: 'Tool image to be attached to Slack posts'
+        required: true
+        type: string
+        
+defaults:
+  run:
+    shell: pwsh
+
+jobs:
+  validation:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          submodules: true
+
+      - name: Validate manifest
+        run: .\helpers\packages-generation\manifest-validator.ps1 -ManifestPath '.\versions-manifest.json'
+
+  check_build:
+    name: Check validation for failures 
+    runs-on: ubuntu-latest
+    needs: [validation]
+    if: failure()
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          submodules: true
+
+      - name: Send Slack notification if validation fails
+        run: |
+          $pipelineUrl = "$env:GITHUB_SERVER_URL/$env:GITHUB_REPOSITORY/actions/runs/$env:GITHUB_RUN_ID"
+          $message = "The validation of ${{ inputs.tool-name }} manifest failed. \nLink to the pipeline: $pipelineUrl"
+          .\helpers\get-new-tool-versions\send-slack-notification.ps1 -Url "${{ secrets.SLACK_CHANNEL_URL }}" `
+                                                                      -ToolName "${{ inputs.tool-name }}" `
+                                                                      -Text "$message" `
+                                                                      -ImageUrl "${{ inputs.image-url }}"