Dependabot declares a changed version constraint as a "bump"

### Is there an existing issue for this?

- [x] I have searched the existing issues

### Package ecosystem

Docker

### Package manager version

_No response_

### Language version

_No response_

### Manifest location and content before the Dependabot update

_No response_

### dependabot.yml content

```yaml
- package-ecosystem: "docker"
directory: "/"
schedule:
interval: "weekly"
labels:
- "dependencies"
- "release/patch"
groups:
dependabot-patch-and-minor-docker:
update-types:
- "minor"
- "patch"
```

### Updated dependency

`bump elixir from 1.18.3-otp-27-alpine to 1.18-otp-27-alpine in the dependabot-patch-and-minor-docker group`

### What you expected to see, versus what you actually saw

We are using the `elixir` Docker image at `elixir:1.18.3-otp-27-alpine` for one of our images, but Docker keeps opening _incorrect_ upgrades which change the version constraint to be less specific than we have requested. (An example from one repo has been provided, but this is happening across multiple repos.)

### Native package manager behavior

_No response_

### Images of the diff or a link to the PR, issue, or logs

_No response_

### Smallest manifest that reproduces the issue

_No response_

The issue names no repository files, tests, or entry points and provides no smallest manifest or linked reproduction. Start by reproducing the Docker update with the supplied dependabot.yml and the Elixir image tag, then trace the Docker dependency update handling. Done means a version constraint such as 1.18.3-otp-27-alpine is not changed to the less-specific 1.18-otp-27-alpine form.

Written by the indexing model from the issue text.