Add PR validations to improve maintainability (#143)

Resolves #26

.github/workflows/pull_request.yml

@@ -56,3 +56,19 @@ jobs:
       upload-code-coverage: true
     secrets:
       CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
+  danger-check:
+    runs-on: ubuntu-latest
+    permissions:
+      pull-requests: write
+      statuses: write
+    steps:
+      - name: 'Checkout Repository'
+        uses: actions/checkout@v4
+      - name: Danger
+        uses: danger/kotlin@1.3.1
+        with:
+          run-mode: ci
+          dangerfile: Dangerfile.df.kts
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+

Dangerfile.df.kts

@@ -0,0 +1,17 @@
+@file:Suppress("ktlint:standard:no-wildcard-imports")
+
+import systems.danger.kotlin.*
+
+danger(args) {
+  onGitHub {
+    val prLabels = issue.labels
+    when (prLabels.size) {
+      0 -> fail("PR must have labels")
+      1 ->
+        prLabels.find { it.name.equals("ignore", ignoreCase = true) }?.let {
+          warn("PR must have labels other then '[${it.name}](${it.url})'")
+        }
+      else -> {}
+    }
+  }
+}