Deprecating Dependabot elm 0.18 support (#19133)

Author: asciimike

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

@@ -11,7 +11,7 @@ Cargo          | `cargo`          | v1               | **✓** | **✓** | |
 Composer       | `composer`       | v1, v2           | **✓** | **✓** | |
 Docker         | `docker`         | v1               | **✓** | **✓** | |
 Hex            | `mix`            | v1               | | **✓** | |
-elm-package    | `elm`            | v0.18, v0.19     | **✓** | **✓** | |
+elm-package    | `elm`            | v0.19            | **✓** | **✓** | |
 git submodule  | `gitsubmodule`   | N/A (no version) | **✓** | **✓** | |
 GitHub Actions | `github-actions` | N/A (no version) | **✓** | **✓** | |
 Go modules     | `gomod`          | v1               | **✓** | **✓** | **✓** |