Update heroku/buildpacks-ruby to v4.0.2 (#624)

## heroku/ruby

### Fixed

- Ruby pre-release verssions like `3.4.0.rc1` now work as expected. ([#372](heroku/buildpacks-ruby#372))
- Layer metadata deserialization to Rust structs is now using `#[serde(deny_unknown_fields)]` this prevents the accidental scenario where metadata containing a superset of fields could accidentally be deserialized to the wrong struct. It's unlikely this is currently happening with the current buildpack, but it's a possibly-observable difference so it's being listed ([#371](heroku/buildpacks-ruby#371))

Co-authored-by: heroku-linguist[bot] <136119646+heroku-linguist[bot]@users.noreply.github.com>

builder-20/builder.toml

@@ -47,7 +47,7 @@ version = "0.20.5"
 
 [[buildpacks]]
   id = "heroku/ruby"
-  uri = "docker://docker.io/heroku/buildpack-ruby@sha256:8d80f5d08664e1d0558e8e964c3e14c1fca7195548f2462e3fe32c354bc9ded3"
+  uri = "docker://docker.io/heroku/buildpack-ruby@sha256:636daa054da47cc01c4413aa03d902f888ac08198e90742ba2662262d772a67a"
 
 [[buildpacks]]
   id = "heroku/scala"
@@ -80,7 +80,7 @@ version = "0.20.5"
     optional = true
   [[order.group]]
     id = "heroku/ruby"
-    version = "4.0.1"
+    version = "4.0.2"
   [[order.group]]
     id = "heroku/procfile"
     version = "3.1.2"

builder-22/builder.toml

@@ -51,7 +51,7 @@ version = "0.20.5"
 
 [[buildpacks]]
   id = "heroku/ruby"
-  uri = "docker://docker.io/heroku/buildpack-ruby@sha256:8d80f5d08664e1d0558e8e964c3e14c1fca7195548f2462e3fe32c354bc9ded3"
+  uri = "docker://docker.io/heroku/buildpack-ruby@sha256:636daa054da47cc01c4413aa03d902f888ac08198e90742ba2662262d772a67a"
 
 [[buildpacks]]
   id = "heroku/scala"
@@ -89,7 +89,7 @@ version = "0.20.5"
     optional = true
   [[order.group]]
     id = "heroku/ruby"
-    version = "4.0.1"
+    version = "4.0.2"
   [[order.group]]
     id = "heroku/procfile"
     version = "3.1.2"

builder-24/builder.toml

@@ -51,7 +51,7 @@ mirrors = ["public.ecr.aws/heroku/heroku:24"]
 
 [[buildpacks]]
   id = "heroku/ruby"
-  uri = "docker://docker.io/heroku/buildpack-ruby@sha256:8d80f5d08664e1d0558e8e964c3e14c1fca7195548f2462e3fe32c354bc9ded3"
+  uri = "docker://docker.io/heroku/buildpack-ruby@sha256:636daa054da47cc01c4413aa03d902f888ac08198e90742ba2662262d772a67a"
 
 [[buildpacks]]
   id = "heroku/scala"
@@ -89,7 +89,7 @@ mirrors = ["public.ecr.aws/heroku/heroku:24"]
     optional = true
   [[order.group]]
     id = "heroku/ruby"
-    version = "4.0.1"
+    version = "4.0.2"
   [[order.group]]
     id = "heroku/procfile"
     version = "3.1.2"