Adds the Official Gradle Wrapper Validation GitHub Action

The idea is to alert when a PR introduces non official gradle wrapper
to prevent _social engineering supply chain attack_.

See: https://github.com/gradle/wrapper-validation-action

.editorconfig

@@ -6,3 +6,9 @@ insert_final_newline = true
 trim_trailing_whitespace = true
 indent_style = space
 indent_size = 4
+
+[{*.yml,*.yaml}]
+indent_size = 2
+ij_continuation_indent_size = 2
+ij_yaml_keep_indents_on_empty_lines = false
+ij_yaml_keep_line_breaks = true

.github/workflows/gradle-wrapper-validation.yml

@@ -0,0 +1,10 @@
+name: "Validate Gradle Wrapper"
+on: [push, pull_request]
+
+jobs:
+  validation:
+    name: "Validation"
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: gradle/wrapper-validation-action@v1