Adding bundler v2 support (#18500)

Author: asciimike

data/reusables/dependabot/supported-package-managers.md

@@ -6,7 +6,7 @@ The following table shows, for each package manager:
 
 Package manager | YAML value      | Supported versions | Private repositories | Private registries | Vendoring 
 ---------------|------------------|------------------|:---:|:---:|:---:
-Bundler        | `bundler`        | v1               | | **✓** | **✓** |
+Bundler        | `bundler`        | v1, v2           | | **✓** | **✓** |
 Cargo          | `cargo`          | v1               | **✓** | **✓** | |
 Composer       | `composer`       | v1, v2           | **✓** | **✓** | |
 Docker         | `docker`         | v1               | **✓** | **✓** | |